feat(chat): save and view chat history — admin-only saved_chats, History page, open-a-chat return

tests/unit/test_caching.py

@@ -185,6 +185,30 @@ def test_empty_static_dir_is_dev(tmp_path) -> None:
     assert asset_version(str(empty)) == "dev"
 
 
+# ---------------------------------------------------------------------------
+# HTML_PAGES registration
+# ---------------------------------------------------------------------------
+
+
+def test_html_pages_include_history() -> None:
+    """Phase 50: the History page is registered in HTML_PAGES — without
+    this entry it would serve unversioned asset refs, which the
+    immutable-for-a-year asset caching would pin to stale CSS after a
+    deploy (the phase-35 git-sources lesson). The entry is ADDED —
+    every pre-phase-50 page stays registered."""
+    for path in (
+        "/",
+        "/index.html",
+        "/sources.html",
+        "/document.html",
+        "/login.html",
+        "/tuning.html",
+        "/git-sources.html",
+        "/history.html",
+    ):
+        assert path in caching.HTML_PAGES, f"{path} must be in HTML_PAGES"
+
+
 # ---------------------------------------------------------------------------
 # rewrite_asset_refs (task 02)
 # ---------------------------------------------------------------------------

tests/unit/test_frontend_brand.py

@@ -28,6 +28,7 @@ HTML_PAGES = (
     "document.html",
     "login.html",
     "git-sources.html",
+    "history.html",  # phase 50: the admin saved-chats page
 )
 
 

tests/unit/test_history_page.py

@@ -0,0 +1,428 @@
+"""Unit: the phase-50 task-04 History-page contract.
+
+The browser behavior itself is E2E-gated by the story suite (task 05);
+like the other frontend-adjacent unit files, this module pins the
+JS/CSS/HTML markers the History page depends on, so a silent
+regression is caught without a browser:
+
+* the anonymous no-fetch gate (the gate in, the table out, and the
+  single ``GET /api/chats`` fetch lives ONLY in ``loadChats`` —
+  unreachable from the anonymous branch);
+* the inline two-step Delete (the "Delete? [Yes] [No]" pair, focus to
+  Yes, the row kept on No / a failed request, ``Deleted "<title>".``
+  on success) and the ``window.confirm`` absence in ``history.js``
+  (owner-locked 2026-08-29: no native confirm dialog on this page);
+* the ``/?chat=<id>`` Open-link href shape (TODO.md L5 — "return to
+  that history with a click");
+* ``#nav-history`` on ALL SEVEN pages (the phase-34 one-bar contract)
+  + ``header.js``'s reveal-for-admin block;
+* the full-width table CSS (AGENTS.md rule 5) + the confirm pair +
+  the empty-state row.
+
+The Containerfile stage-1 coverage (history.html copied, history.js
+bundled) is pinned dynamically by
+``tests/integration/test_containerfile_assets.py`` — a page or module
+missing from stage 1 fails there.
+"""
+from __future__ import annotations
+
+import re
+from pathlib import Path
+
+FRONTEND = Path(__file__).resolve().parents[2] / "frontend"
+ASSETS = FRONTEND / "assets"
+
+INDEX_HTML = FRONTEND / "index.html"
+SOURCES_HTML = FRONTEND / "sources.html"
+GIT_SOURCES_HTML = FRONTEND / "git-sources.html"
+TUNING_HTML = FRONTEND / "tuning.html"
+DOCUMENT_HTML = FRONTEND / "document.html"
+LOGIN_HTML = FRONTEND / "login.html"
+HISTORY_HTML = FRONTEND / "history.html"
+HISTORY_JS = ASSETS / "history.js"
+HEADER_JS = ASSETS / "header.js"
+STYLES_CSS = ASSETS / "styles.css"
+
+#: The phase-34 one-bar contract + the new History page: SEVEN pages.
+ALL_PAGES = (
+    INDEX_HTML,
+    SOURCES_HTML,
+    GIT_SOURCES_HTML,
+    TUNING_HTML,
+    DOCUMENT_HTML,
+    LOGIN_HTML,
+    HISTORY_HTML,
+)
+
+
+def _text(path: Path) -> str:
+    assert path.is_file(), f"missing frontend file: {path}"
+    return path.read_text(encoding="utf-8")
+
+
+def _js() -> str:
+    return _text(HISTORY_JS)
+
+
+def _css() -> str:
+    return _text(STYLES_CSS)
+
+
+def _fn(js: str, name: str) -> str:
+    """The source of a top-level ``function <name>(...)`` (to its close)."""
+    start = js.find(f"function {name}(")
+    assert start != -1, f"{name}() must exist in history.js"
+    return js[start : js.find("\n}\n", start) + 4]
+
+
+def _nav_history_tag(html: str) -> str:
+    tag = re.search(r'<a[^>]*id="nav-history"[^>]*>', html)
+    assert tag, "the #nav-history link is missing"
+    return tag.group(0)
+
+
+# ---------- the #nav-history link: all seven pages ----------
+
+
+def test_nav_history_present_on_all_seven_pages() -> None:
+    """The phase-34 one-bar contract extended by phase 50: the admin-only
+    History link SHIPS hidden (revealed by header.js for admin) on every
+    page, after the Tuning link, pointing at /history.html. The page's
+    own link is the active one (is-active + aria-current)."""
+    for html in ALL_PAGES:
+        text = _text(html)
+        tag = _nav_history_tag(text)
+        assert 'href="/history.html"' in tag
+        assert "hidden" in tag, f"{html.name}: #nav-history must ship hidden"
+        # Placed after the Tuning link (the owner-locked position).
+        assert text.find('id="nav-tuning"') < text.find('id="nav-history"'), (
+            f"{html.name}: #nav-history must follow #nav-tuning"
+        )
+    # The history page is the only one whose link is active.
+    for html in ALL_PAGES:
+        tag = _nav_history_tag(_text(html))
+        if html.name == "history.html":
+            assert 'class="nav-link is-active"' in tag
+            assert 'aria-current="page"' in tag
+        else:
+            assert "is-active" not in tag, (
+                f"{html.name}: no nav link is current there"
+            )
+
+
+def test_nav_history_count_is_exactly_seven_pages() -> None:
+    """The pin counting occurrences across ``frontend/*.html`` — exactly
+    one ``id="nav-history"`` per page, seven pages, no duplicates and no
+    extra page that forgot (or added twice)."""
+    total = 0
+    for html in sorted(FRONTEND.glob("*.html")):
+        count = html.read_text(encoding="utf-8").count('id="nav-history"')
+        assert count in (0, 1), f"{html.name}: #nav-history appears {count} times"
+        total += count
+    assert total == 7, f"expected #nav-history on 7 pages, found {total}"
+
+
+def test_header_js_reveals_nav_history_for_admin() -> None:
+    """header.js reveals #nav-history for admin exactly like
+    #nav-tuning — the same ship-hidden / reveal-for-admin contract,
+    inside initSharedHeader (null-safe: a page without the link is a
+    no-op)."""
+    js = _text(HEADER_JS)
+    fn = js.find("function initSharedHeader")
+    assert fn != -1
+    body = js[fn : js.find("\n}", fn)]
+    assert 'querySelector("#nav-history")' in body
+    assert "navHistory.hidden = !admin" in body
+
+
+# ---------- history.html: the page scaffold ----------
+
+
+def test_history_page_scaffold_and_landmarks() -> None:
+    """The standard page scaffold (AGENTS.md rule 5): skip link, the
+    shared header, the steering panel + announcer (phase 34 — ships on
+    every page), the page-head, the gate (ship-hidden), the
+    role="status" live region, and the table inside the
+    .table-wrap card. Footer with the version span (the index.html
+    shape)."""
+    html = _text(HISTORY_HTML)
+    assert '<a class="skip-link" href="#main">' in html
+    assert 'class="app-header"' in html
+    assert 'nav class="app-nav" id="app-nav" aria-label="Primary"' in html
+    tag = re.search(r'<section[^>]*id="steering-panel"[^>]*>', html)
+    assert tag and "hidden" in tag.group(0), "the steering panel ships hidden"
+    assert re.search(r'<p[^>]*id="steering-announcer"[^>]*role="status"[^>]*>', html)
+    assert "<main id=\"main\" class=\"app-main\" tabindex=\"-1\">" in html
+    assert '<h1>Saved chats</h1>' in html
+    # The anonymous gate — the #sources-gate pattern, ship-hidden.
+    gate = re.search(r'<section[^>]*id="history-gate"[^>]*>', html)
+    assert gate and "hidden" in gate.group(0), "#history-gate must ship hidden"
+    assert 'href="/login.html?next=/history.html"' in html, (
+        "the gate's Sign in returns to the History page (no-JS fallback)"
+    )
+    # The action-feedback live region.
+    assert re.search(r'<span[^>]*id="history-status"[^>]*role="status"[^>]*>', html)
+    # The table wrapper: the .table-wrap card (scrollable) with its
+    # own id, a labeled region, focusable.
+    wrap = re.search(r'<div[^>]*class="table-wrap history-table-wrap"[^>]*>', html)
+    assert wrap, "the table must live in the .table-wrap card"
+    assert 'id="history-table-wrap"' in wrap.group(0)
+    assert 'role="region"' in wrap.group(0) and 'tabindex="0"' in wrap.group(0)
+    # Footer with the version span.
+    assert 'class="footer-version" id="app-version"' in html
+
+
+def test_history_table_skeleton() -> None:
+    """The table skeleton: ``.history-table`` with the four columns —
+    Title | Messages | Updated | Actions (the Actions header text is
+    visually-hidden — the row buttons carry their own aria-labels) —
+    and the empty-state row (ship-hidden, the exact copy)."""
+    html = _text(HISTORY_HTML)
+    assert '<table class="history-table">' in html
+    for col in ('<th scope="col">Title</th>', '<th scope="col">Messages</th>',
+                '<th scope="col">Updated</th>'):
+        assert col in html
+    actions_th = re.search(
+        r'<th scope="col">([^<]*)<span class="visually-hidden">Actions</span></th>',
+        html,
+    )
+    assert actions_th, "the Actions column header must be visually-hidden text"
+    assert actions_th.group(1) == "", "no visible text beside the hidden header"
+    # The empty-state row: ship-hidden, colspan 4, the exact copy.
+    row = re.search(r'<tr[^>]*class="history-empty-row"[^>]*>', html)
+    assert row, "the empty-state row must ship in the skeleton"
+    assert "hidden" in row.group(0)
+    assert 'id="history-empty-row"' in row.group(0)
+    assert "<td colspan=\"4\">" in html
+    assert (
+        "No saved chats yet — finish a conversation and press"
+        " <strong>Save</strong> in the chat."
+    ) in html
+
+
+def test_history_page_scripts_and_no_cdn() -> None:
+    """Script load order (the house pattern): brand.js classic FIRST,
+    the history.js module second, NO direct header.js <script> tag
+    (single-evaluation design — history.js imports it relatively).
+    No-CDN rule (AGENTS.md rule 6): no external script/link tags."""
+    html = _text(HISTORY_HTML)
+    srcs = re.findall(r'<script[^>]*src="([^"]+)"', html)
+    assert srcs == ["assets/brand.js", "/assets/history.js"], (
+        f"history.html must load brand.js (classic, first) + the history.js "
+        f"module, got {srcs}"
+    )
+    js = _js()
+    assert 'from "./header.js"' in js, (
+        "history.js must import the shared header module relatively"
+    )
+    assert '"/assets/header.js"' not in js
+    assert 'src="http' not in html and 'href="http' not in html, (
+        "no CDN: every asset is local (AGENTS.md rule 6)"
+    )
+
+
+# ---------- the anonymous no-fetch gate ----------
+
+
+def test_anonymous_boot_makes_no_chats_request() -> None:
+    """The whoami gate in the boot IIFE: ``initSharedHeader()`` first
+    (shared-header contract), then the anonymous branch hides the
+    table, shows the gate, and RETURNS — no ``/api/chats`` request on
+    the wire (the router 403s anonymous; the story E2E pins the
+    request log). Only the admin path reaches ``loadChats()``. The
+    single ``fetch("/api/chats")`` in the file lives in loadChats."""
+    js = _js()
+    assert js.count('fetch("/api/chats")') == 1, (
+        "exactly ONE list fetch — the anonymous path must never add one"
+    )
+    load = _fn(js, "loadChats")
+    assert 'fetch("/api/chats")' in load, "the list fetch lives in loadChats"
+
+    boot = js[js.find("(async () => {"):]
+    assert boot, "the boot IIFE must exist"
+    assert "await initSharedHeader()" in boot
+    gate_i = boot.find("if (!(await fetchIsAdmin()))")
+    assert gate_i != -1, "the whoami gate must run in boot"
+    # The anonymous branch: gate in, table out, then a bare return —
+    # and NO fetch call anywhere inside it.
+    branch = boot[gate_i : boot.find("return;", gate_i)]
+    assert "fetch(" not in branch, "the anonymous branch must not fetch anything"
+    assert "tableWrap.hidden = true" in branch
+    assert "gateEl.hidden = false" in branch
+    # The admin path: the gate hides, then the list loads.
+    after = boot[boot.find("return;", gate_i):]
+    assert "gateEl.hidden = true" in after
+    assert "loadChats();" in after
+
+
+def test_admin_load_renders_rows_or_empty_state() -> None:
+    """loadChats: a 0-row fetch (and non-2xx / a network failure)
+    reveals the empty-state row; a populated fetch renders one row per
+    chat, in the server's order (latest activity first)."""
+    js = _js()
+    load = _fn(js, "loadChats")
+    # Every no-data outcome lands on the empty state.
+    assert load.count("showEmptyState()") == 3, (
+        "network failure, non-2xx and a 0-row list all show the empty state"
+    )
+    assert "chats.length" in load
+    assert "makeRow(chat)" in load
+    empty = _fn(js, "showEmptyState")
+    assert "emptyRow.hidden = false" in empty
+
+
+# ---------- the /?chat=<id> Open link ----------
+
+
+def test_open_link_is_the_title_with_chat_href() -> None:
+    """makeRow: the Title cell is the Open link — ``/?chat=<id>``
+    ("return to that history with a click", TODO.md L5) — rendered
+    through textContent (the auto-title is user-derived; never
+    innerHTML). The Updated cell carries the locale date+time with the
+    full ISO in the title attribute; Messages is the message_count."""
+    js = _js()
+    row = _fn(js, "makeRow")
+    assert 'link.href = "/?chat=" + chat.id' in row, (
+        "the Open link returns to /?chat=<id> (task 03's boot load)"
+    )
+    assert 'link.className = "history-title-link"' in row
+    assert "link.textContent = chat.title" in row, "XSS contract: textContent only"
+    assert 'innerHTML' not in row, "makeRow must never build HTML"
+    assert "String(chat.message_count)" in row
+    assert "updatedTd.title = chat.updated_at" in row, "full ISO on hover"
+    assert "fmtDate(chat.updated_at)" in row
+    assert "link.title" in row or "titleTd.title = chat.title" in row
+
+
+# ---------- the inline two-step Delete ----------
+
+
+def test_two_step_delete_confirm_pair() -> None:
+    """makeDeleteControl: the first click swaps the Delete button for
+    the "Delete? [Yes] [No]" pair IN PLACE (keyboard-reachable — focus
+    moves to Yes); No restores the Delete button (focus returns); the
+    Delete button carries a labeled aria-name."""
+    js = _js()
+    # Owner-locked 2026-08-29: no native confirm dialog in the file.
+    assert "window.confirm" not in js, "history.js must use the inline two-step only"
+    fn = _fn(js, "makeDeleteControl")
+    assert 'del.className = "history-delete"' in fn
+    assert 'del.setAttribute("aria-label", `Delete saved chat: ${chat.title}`)' in fn
+    assert 'label.textContent = "Delete?"' in fn
+    assert 'yes.className = "history-confirm-yes"' in fn
+    assert 'no.className = "history-confirm-no"' in fn
+    # The shipped state of the actions cell IS the Delete button
+    # (before any click) — a cell that only gains the button on
+    # restore would render an empty Actions column.
+    append = fn.find("cell.appendChild(del)")
+    ret = fn.rfind("return cell")
+    assert -1 < append < ret, "the Delete button is appended before the return"
+    # The swap + the focus handoff.
+    assert "cell.replaceChildren(label, yes, no)" in fn
+    yes_swap = fn.find("cell.replaceChildren(label, yes, no)")
+    assert fn.find("yes.focus()", yes_swap) > 0, "focus moves to Yes after the swap"
+    # No (and the restore helper) bring the Delete button back, focused.
+    restore_start = fn.find("function restoreDelete")
+    restore_end = fn.find("\n  }", restore_start)
+    restore = fn[restore_start:restore_end]
+    assert "cell.replaceChildren(del)" in restore
+    assert "del.focus()" in restore
+    assert 'no.addEventListener("click", restoreDelete)' in fn
+
+
+def test_confirmed_delete_outcomes() -> None:
+    """confirmDelete: double-fire guarded; 2xx → the row is removed +
+    the empty-state row reappears when it was the last + the live
+    region `Deleted "<title>".`; a 404 (already gone) drops the stale
+    row and says so; any other failure / a network error KEEPS the row
+    (restore) and lands the error line."""
+    js = _js()
+    fn = _fn(js, "confirmDelete")
+    assert "yesBtn.disabled = true" in fn
+    assert "fetch(`/api/chats/${chat.id}`, { method: \"DELETE\" })" in fn
+    # Success: remove + empty-state check + the exact live-region line.
+    assert "row.remove()" in fn
+    assert "showEmptyIfLast()" in fn
+    assert 'announce(`Deleted "${chat.title}".`)' in fn
+    # 404: the row is stale — drop it, no restore. (The branch slices
+    # stop at the NEXT branch boundary — a template-literal `}` inside
+    # an announce line must not end the slice early.)
+    nf = fn.find("r.status === 404")
+    assert nf != -1, "the 404 branch must be handled"
+    notok = fn.find("if (!r.ok)")
+    nf_branch = fn[nf:notok]
+    assert "row.remove()" in nf_branch
+    assert "already deleted" in nf_branch
+    assert "restoreDelete()" not in nf_branch
+    # !ok (non-404) and network: the row stays, the button is
+    # retryable, and the error line lands.
+    # !ok (non-404) and network: the row stays, the button is
+    # retryable, and the error line lands. (The try/catch wraps the
+    # FETCH, so it precedes the status branches; the !ok slice runs to
+    # the function's close — the success tail after it carries neither
+    # a restore nor that line.)
+    assert notok != -1
+    notok_branch = fn[notok:]
+    assert "restoreDelete()" in notok_branch
+    assert "try again" in notok_branch
+    # The network-error catch: the reachable? line + the restore (the
+    # catch wraps the fetch, so it precedes the status branches).
+    catch_i = fn.find("} catch {")
+    assert catch_i != -1
+    catch_branch = fn[catch_i : fn.find("if (r.status === 404)")]
+    assert "is the app reachable?" in catch_branch
+    assert "restoreDelete()" in catch_branch
+    # The empty-state row reappears exactly when the last data row is
+    # gone (the hidden empty row itself ships in the tbody).
+    empty = _fn(js, "showEmptyIfLast")
+    assert "querySelectorAll(\"tr\").length > 1" in empty
+
+
+# ---------- the table CSS ----------
+
+
+def test_history_table_css_full_width_and_palette() -> None:
+    """styles.css: .history-table is the full-width sources-table family
+    (width 100%, --line borders, the brand-soft thead, row hover); the
+    title link is the accent link (brand-ink, focus-visible); the
+    confirm pair is Yes-on-error-rose + No-ghost; the empty-state row
+    is the muted centered message. Every pair is Phase-08 AA
+    (brand-ink/brand-soft 6.9:1, err 9.1:1, ink-soft >=6.9:1)."""
+    css = _css()
+    block = re.search(r"\.history-table \{([\s\S]*?)\n\}", css)
+    assert block, "styles.css must style .history-table"
+    body = block.group(1)
+    assert "width: 100%" in body, "the table is FULL-WIDTH (AGENTS.md rule 5)"
+    assert "min-width: 640px" in body
+    th = re.search(r"\.history-table th \{([\s\S]*?)\n\}", css)
+    assert th and "var(--brand-soft)" in th.group(1) and "var(--brand-ink)" in th.group(1)
+    hover = re.search(r"\.history-table tbody tr:hover \{([^}]*)\}", css)
+    assert hover, "row hover is part of the table family"
+    link = re.search(r"\.history-title-link \{([\s\S]*?)\n\}", css)
+    assert link and "var(--brand-ink)" in link.group(1), "the Open link is the accent link"
+    assert re.search(r"\.history-title-link:focus-visible \{[^}]*outline[^}]*3px", css), (
+        "the Open link keeps a :focus-visible outline"
+    )
+    yes = re.search(r"\.history-confirm-yes \{([\s\S]*?)\n\}", css)
+    assert yes, "the confirm Yes button must be styled"
+    ybody = yes.group(1)
+    assert "var(--err-bg)" in ybody and "var(--err-ink)" in ybody and "var(--err-line)" in ybody
+    no = re.search(r"\.history-confirm-no \{([\s\S]*?)\n\}", css)
+    assert no and "background: transparent" in no.group(1), "No is the ghost"
+    empty = re.search(r"\.history-empty-row td \{([\s\S]*?)\n\}", css)
+    assert empty, "the empty-state row must be styled"
+    ebody = empty.group(1)
+    assert "text-align: center" in ebody and "var(--ink-soft)" in ebody
+
+
+def test_history_table_mobile_behavior() -> None:
+    """≤640px (the phase-07 responsive contract): the table keeps its
+    full width (the .table-wrap's horizontal scroll already covers
+    it) and the actions cell wraps so the two-step confirm pair fits
+    the phone width."""
+    css = _css()
+    mobile = re.search(r"@media \(max-width: 640px\) \{([\s\S]*?)\n\}\n", css)
+    assert mobile, "the mobile media query must exist"
+    mbody = mobile.group(1)
+    assert ".history-actions-cell { white-space: normal; }" in mbody
+    assert ".history-actions { flex-wrap: wrap; }" in mbody

tests/unit/test_save_chat_ui.py

@@ -0,0 +1,293 @@
+"""Unit: the phase-50 task-03 save-chat contract on the chat page.
+
+The browser behavior itself is E2E-gated by the story suite (task 05);
+like the other frontend-adjacent unit files, this module pins the
+JS/CSS/HTML markers the save/load contract depends on, so a silent
+regression is caught without a browser:
+
+* the ``currentChatId`` lifecycle (set on create/open, cleared by New
+  chat and by the 404-PUT fallback);
+* the upsert branch (PUT when linked, POST when not, the 404→recreate
+  fallback, the live-region feedback strings);
+* the boot-load precedence (a valid ``?chat=`` uuid + admin replaces the
+  local restore and mirrors it to localStorage; anonymous / invalid /
+  404 / network → the local restore);
+* the ship-hidden / reveal-for-admin gate on ``#save-chat-btn``.
+"""
+from __future__ import annotations
+
+import re
+from pathlib import Path
+
+FRONTEND = Path(__file__).resolve().parents[2] / "frontend"
+APP_JS = FRONTEND / "assets" / "app.js"
+INDEX_HTML = FRONTEND / "index.html"
+SOURCES_HTML = FRONTEND / "sources.html"
+GIT_SOURCES_HTML = FRONTEND / "git-sources.html"
+DOCUMENT_HTML = FRONTEND / "document.html"
+LOGIN_HTML = FRONTEND / "login.html"
+TUNING_HTML = FRONTEND / "tuning.html"
+STYLES_CSS = FRONTEND / "assets" / "styles.css"
+
+
+def _js() -> str:
+    return APP_JS.read_text(encoding="utf-8")
+
+
+def _css() -> str:
+    return STYLES_CSS.read_text(encoding="utf-8")
+
+
+def _index() -> str:
+    return INDEX_HTML.read_text(encoding="utf-8")
+
+
+def _fn(js: str, name: str) -> str:
+    """The source of a top-level ``function <name>(...)`` (to its close)."""
+    start = js.find(f"function {name}(")
+    assert start != -1, f"{name}() must exist in app.js"
+    return js[start : js.find("\n}\n", start) + 4]
+
+
+# ---------- the Save button on the chat page ----------
+
+
+def test_save_button_ships_hidden_beside_new_chat() -> None:
+    """#save-chat-btn: a real type=button with the accessible name
+    "Save chat", SHIPPED HIDDEN (app.js reveals it for admin only),
+    beside #new-chat-btn in .chat-shell inside <main>, above
+    #messages — the two chat-shell actions read as a pair. No other
+    page carries it (chat-page only, like New chat)."""
+    html = _index()
+    btn = re.search(r'<button[^>]*id="save-chat-btn"[^>]*>', html)
+    assert btn, "index.html must contain #save-chat-btn"
+    tag = btn.group(0)
+    assert 'type="button"' in tag
+    assert 'aria-label="Save chat"' in tag
+    assert "hidden" in tag, "the button ships hidden (reveal is app.js's job)"
+    # Beside New chat: after it, still inside .chat-shell, above #messages.
+    main_idx = html.find('main id="main"')
+    shell_idx = html.find('class="container chat-shell"')
+    new_idx = html.find('id="new-chat-btn"')
+    messages_idx = html.find('id="messages"')
+    assert -1 < main_idx < shell_idx < new_idx < btn.start() < messages_idx, (
+        "the button must sit beside #new-chat-btn in .chat-shell, above #messages"
+    )
+    for other in (SOURCES_HTML, GIT_SOURCES_HTML, DOCUMENT_HTML, LOGIN_HTML, TUNING_HTML):
+        assert 'id="save-chat-btn"' not in other.read_text(encoding="utf-8"), (
+            f"{other.name}: the Save button is chat-page only"
+        )
+
+
+def test_save_button_css_is_the_exact_new_chat_family() -> None:
+    """styles.css: .save-chat-btn carries the EXACT visual family of
+    .new-chat-btn — solid brand pill (--bg on --brand = 5.2:1, AA),
+    borderless, 999px radius, ≥44px target, hover lightens the brand
+    fill; the ≤640px block mirrors the New chat overrides (label stays
+    visible in .chat-shell, icon hidden there; icon-only elsewhere)."""
+    css = _css()
+    block = re.search(r"\.save-chat-btn \{([\s\S]*?)\n\}", css)
+    assert block, "styles.css must style .save-chat-btn"
+    body = block.group(1)
+    assert "min-height: 44px" in body
+    assert "border-radius: 999px" in body
+    assert "border: 0" in body
+    assert "background: var(--brand)" in body, "same solid brand fill as New chat"
+    assert "color: var(--bg)" in body, "--bg text on --brand = 5.2:1 (AA)"
+    hover = re.search(r"\.save-chat-btn:hover \{([\s\S]*?)\n\}", css)
+    assert hover and "#f55a72" in hover.group(1), "hover lightens the brand fill"
+    svg = re.search(r"\.save-chat-btn svg \{([\s\S]*?)\n\}", css)
+    assert svg and "display: none" in svg.group(1), "icon hidden on desktop (like New chat)"
+    mobile = re.search(r"@media \(max-width: 640px\) \{([\s\S]*?)\n\}", css)
+    assert mobile, "mobile media query missing"
+    mbody = mobile.group(1)
+    assert ".save-chat-btn { padding: 0.4rem 0.3rem; }" in mbody, "squeezes with New chat"
+    assert ".save-chat-label { display: none; }" in mbody
+    assert ".save-chat-btn svg { display: block; }" in mbody
+    assert ".chat-shell .save-chat-label { display: inline; }" in mbody, (
+        "in .chat-shell the label stays visible, as for New chat"
+    )
+    assert ".chat-shell .save-chat-btn svg { display: none; }" in mbody
+
+
+# ---------- currentChatId lifecycle ----------
+
+
+def test_current_chat_id_module_scope_and_lifecycle() -> None:
+    """currentChatId: module scope, string | null — set to the created
+    row's id on a fresh Save (201), set to the opened id on a
+    successful boot load, cleared by "New chat" AND by the 404-PUT
+    fallback (a stale link must never leave the conversation unsaved)."""
+    js = _js()
+    assert "let currentChatId = null" in js, "module-scope link, null = unlinked"
+    # Set on create: the 201 branch links to the created row's id.
+    save_body = _fn(js, "saveCurrentChat")
+    assert "res.status === 201" in save_body
+    assert "currentChatId = String(created.id)" in save_body, (
+        "a fresh Save links to the created row's id"
+    )
+    # Set on open: the boot load links to the fetched id.
+    load_body = _fn(js, "restoreSavedChatFromUrl")
+    assert "currentChatId = chatId" in load_body
+    # Cleared by New chat.
+    new_body = _fn(js, "startNewChat")
+    assert "currentChatId = null" in new_body, "New chat unlinks"
+    # Cleared by the 404-PUT fallback (see the upsert test for the branch).
+    assert "res.status === 404" in save_body
+    assert save_body.count("currentChatId = null") >= 1
+
+
+# ---------- the upsert branch ----------
+
+
+def test_save_upsert_put_when_linked_post_when_not() -> None:
+    """saveCurrentChat: linked → PUT /api/chats/<id> with the messages
+    payload (re-Save updates the SAME row — no title in the body, so the
+    row keeps its current one); unlinked → POST /api/chats (the server
+    auto-titles). The 404 from the PUT unlinks and retries as a create.
+    Empty conversation → no request, live-region "Nothing to save
+    yet."; success → live-region "Conversation saved." (status text
+    only, no banner); 403/5xx/network → the error banner."""
+    js = _js()
+    body = _fn(js, "saveCurrentChat")
+    # No-op first: nothing to save → live-region line, no fetch.
+    noop = body.find('sendStatus.textContent = "Nothing to save yet."')
+    first_fetch = body.find("await fetch(")
+    assert 0 < noop < first_fetch, "the empty-conversation no-op precedes any fetch"
+    assert "if (!conversation.length)" in body
+    # The branch: PUT when linked, POST when not.
+    assert "if (currentChatId)" in body
+    assert '`/api/chats/${currentChatId}`' in body
+    assert 'method: "PUT"' in body
+    assert 'fetch("/api/chats"' in body
+    assert 'method: "POST"' in body
+    put_idx = body.find('method: "PUT"')
+    post_idx = body.find('method: "POST"')
+    assert -1 < put_idx < post_idx, "the PUT (linked) branch precedes the POST fallback"
+    assert '{ messages: conversation }' in body, "the messages payload — no title (keep current)"
+    # The 404→recreate fallback: unlink, then POST again.
+    notfound_idx = body.find("res.status === 404")
+    assert notfound_idx != -1, "the PUT 404 must be handled"
+    fallback = body[notfound_idx:post_idx]
+    assert "currentChatId = null" in fallback, "the stale link is dropped"
+    # Success is status text only — the live region, never stale — and
+    # nothing between the 201 link and the success line may raise a
+    # banner (the !res.ok branch returns before either).
+    assert body.count('sendStatus.textContent = "Conversation saved."') == 1
+    saved_line = 'sendStatus.textContent = "Conversation saved."'
+    between = body[body.find("res.status === 201") : body.find(saved_line)]
+    assert "showErrorBanner" not in between, "no banner on the success path"
+    # Failures raise an actionable banner (non-ok HTTP + network).
+    assert 'showErrorBanner("Couldn\'t save the conversation — is the app reachable?")' in body
+    assert "check you're still signed in and try again" in body, "403/5xx: actionable line"
+    # The double-click guard releases on EVERY outcome.
+    finally_idx = body.rfind("finally")
+    assert finally_idx != -1 and "saveBtn.disabled = false" in body[finally_idx:], (
+        "the button is re-enabled in the finally — never stale"
+    )
+
+
+# ---------- boot-load precedence ----------
+
+
+def test_boot_load_precedence_saved_chat_over_local_restore() -> None:
+    """Inside the boot IIFE: after fetchIsAdmin() + the reveal gate,
+    restoreSavedChatFromUrl() runs; only when it returns false does the
+    phase-14 local restore run. Header init stays first (shared-module
+    contract)."""
+    js = _js()
+    boot_start = js.find("(async () => {")
+    assert boot_start != -1, "the boot IIFE must exist"
+    boot = js[boot_start:]
+    init_i = boot.find("await initSharedHeader();")
+    admin_i = boot.find("isAdmin = await fetchIsAdmin();")
+    reveal_i = boot.find("saveBtn.hidden = !isAdmin")
+    saved_i = boot.find("await restoreSavedChatFromUrl();")
+    local_i = boot.find("restoreConversation();")
+    assert -1 < init_i < admin_i < reveal_i < saved_i < local_i, (
+        "boot order: header init → whoami → Save reveal → ?chat= load → local fallback"
+    )
+    assert "if (!openedSaved) restoreConversation();" in boot, (
+        "the local restore runs ONLY when the saved-chat load did not open"
+    )
+
+
+def test_boot_load_gates_valid_uuid_and_admin_only() -> None:
+    """restoreSavedChatFromUrl: a VALID uuid + admin is the ONLY
+    fetch path — invalid/absent ?chat= and anonymous short-circuit to
+    false (no request: the gate would 403). On 200 the messages
+    REPLACE the local conversation, render through the SAME
+    renderStoredMessage loop (pixel-identical restore), link
+    currentChatId, and mirror to localStorage. 404/network/malformed/
+    empty → banner + false (the local restore then runs)."""
+    js = _js()
+    body = _fn(js, "restoreSavedChatFromUrl")
+    # The gates, in order: param present → valid uuid → admin.
+    assert '.get("chat")' in body, "the ?chat= param"
+    assert "UUID_RE.test(chatId)" in body, "a valid uuid only"
+    assert "!isAdmin" in body, "admin only (no fetch for anonymous)"
+    gate = body.find("!isAdmin")
+    fetch_i = body.find('fetch(`/api/chats/${chatId}`)')
+    assert -1 < gate < fetch_i, "the gates short-circuit BEFORE the fetch"
+    assert "const UUID_RE" in js, "the uuid pattern is module-level"
+    # On success: replace → render through the SAME loop → link → mirror.
+    assert "conversation = messages" in body, "the saved messages REPLACE the local conversation"
+    assert "renderStoredMessage(m)" in body, "the SAME renderStoredMessage path as local restore"
+    assert "markLastRetryable()" in body, "parity with local restore: Retry on the last bubble"
+    save_mir = body.find("saveConversation()")
+    link_i = body.find("currentChatId = chatId")
+    assert -1 < link_i < save_mir, "link first, then mirror to localStorage"
+    # Failure: the exact banner line, then false (→ local restore). The
+    # gate line returns false directly; the 404/network, malformed-body
+    # and empty-payload paths all route through the banner helper.
+    banner_line = 'showErrorBanner("That saved chat isn\'t available — it may have been deleted.")'
+    assert banner_line in body
+    assert "return false" in body, "invalid/absent param or anonymous → no fetch, local restore"
+    assert body.count("return unavailable()") == 4, (
+        "network, non-ok (404/403/5xx), malformed body and empty payload all fall back"
+    )
+    # The ?chat= param is a one-shot boot instruction: the success path
+    # normalizes the URL back to / so a later refresh (or "New chat" +
+    # refresh) restores the LOCAL session instead of re-opening the row.
+    assert 'history.replaceState(null, "", "/")' in body, (
+        "a consumed ?chat= must not linger in the URL"
+    )
+    # The defensive filter keeps a corrupted stored row from poisoning the
+    # restore (same shape check as loadStoredConversation).
+    assert 'm.who === "user" || m.who === "brain"' in body
+    assert 'typeof m.text === "string"' in body
+
+
+# ---------- the reveal gate ----------
+
+
+def test_save_button_revealed_only_for_admin() -> None:
+    """The ship-hidden/reveal-for-admin contract: app.js queries
+    #save-chat-btn, binds the click to saveCurrentChat, and the boot
+    IIFE sets saveBtn.hidden = !isAdmin (phase 16 absent-not-hidden —
+    hidden is display:none, no trace for anonymous)."""
+    js = _js()
+    assert 'document.querySelector("#save-chat-btn")' in js
+    assert 'saveBtn?.addEventListener("click", saveCurrentChat)' in js
+    assert "saveBtn.hidden = !isAdmin" in js, "revealed for admin only, at boot"
+    # The reveal happens in the boot IIFE (after whoami), not at module
+    # evaluation (isAdmin is false there).
+    boot_start = js.find("(async () => {")
+    reveal = js.find("saveBtn.hidden = !isAdmin")
+    assert boot_start < reveal, "the reveal must run at boot, after whoami resolves"
+
+
+def test_boot_load_adds_no_direct_storage_access() -> None:
+    """The localStorage accesses stay EXACTLY the phase-14 three
+    (loadStoredConversation / saveConversation / clearStoredConversation)
+    — the saved-chat mirror goes through saveConversation(), so the
+    house failure-safety pin (exactly 3, all try-wrapped) holds."""
+    js = _js()
+    accesses = list(re.finditer(r"localStorage\.(?:getItem|setItem|removeItem)", js))
+    assert len(accesses) == 3, f"expected exactly 3 localStorage accesses, got {len(accesses)}"
+
+
+def test_no_cdn_added() -> None:
+    """AGENTS.md rule 6: the Save button adds no external script/link."""
+    index = _index()
+    assert 'src="http' not in index and 'href="http' not in index

tests/unit/test_steering_toggle_removal.py

@@ -22,8 +22,8 @@ ASSETS = FRONTEND / "assets"
 
 HEADER_JS = ASSETS / "header.js"
 
-#: All six pages carry the shared header block (phase 34's five pages +
-#: phase 35's git-sources page).
+#: All seven pages carry the shared header block (phase 34's five pages
+#: + phase 35's git-sources page + phase 50's History page).
 PAGES = (
     FRONTEND / "index.html",
     FRONTEND / "sources.html",
@@ -31,6 +31,7 @@ PAGES = (
     FRONTEND / "git-sources.html",
     FRONTEND / "login.html",
     FRONTEND / "tuning.html",
+    FRONTEND / "history.html",
 )