phase: 91_admin_theme_tab

All verification is complete — this pass needed no code changes. Final report:

**Phase 91 — Admin Theme tab: final verification pass (all 6 tasks already in `complete/`)**

- Verified pre-paint theming end-to-end: `ui_settings` store + resolver, admin `GET/PUT /api/ui-settings`, `CachingMiddleware` inline-`<style id="bor-theme">` injection before `</head>` (incl. `/shared/<token>` prefix branch, unit-pinned), CSP sha256 exemption for the inline tag, Theme tab shell + `theme.js` editor, CSS-file theming fully retired.
- No defects found; zero changes made — working tree left exactly as the task executors left it.
- Tests: `uv run pytest --cov=app` → 1841 passed, 0 failed (TOTAL coverage **99%**; theming/ui_settings/caching all 100%); `uv run pytest tests/e2e/test_admin_theme_tab.py -v --no-cov` → **5 passed** in isolation.
- Lint/types: `uv run ruff check .` → All checks passed; `uv run pyright` → 0 errors, 0 warnings.
- Criteria: (1) unset deployment byte-identical, no `#bor-theme` anywhere — ✓ (unit no-op test + E2E reset byte-compare); `rg "BOR_THEME|themes/"` → single hit is the permitted doc-history comment in `frontend/index.html`. (2) admin-only gate + 403s for anonymous and token users — ✓ (E2E test 3). (3) saved theme inline before `</head>` on every page incl. `/shared/<token>`, computed `--brand` on first paint for admin + anonymous — ✓ (E2E test 2 + unit). (4) reset → byte-identical; 5 contrast pairs warn <4.5:1, non-blocking — ✓ (E2E tests 4–5). (5) suite green, >90% coverage, lint clean — ✓. (6) commit deferred to harness per rules.
- Notable: `.agents/PLAN.md` is absent from the repo — the phase overview's Design section was used as the binding spec; no deviation resulted.
- Next pending phase: **none** — 91 is the last phase in `todo/`.

app/config.py

@@ -48,12 +48,11 @@ class Settings(BaseSettings):
 
     # --- UI customization (phase 62, TODO L3) ---
     # Defaults are the phase-61 neutral copy — UNSET => byte-identical UI.
+    # (Phase 91, task 03: the retired CSS-file theme env var is gone —
+    # the admin Theme tab is the only theming surface; a leftover value
+    # in a deployment's .env is simply ignored.)
     input_placeholder: str = "Ask me anything…"
     footer_text: str = "Powered by self-hosted models"
-    #: Theme file NAME under frontend/assets/themes/ (e.g. "indigo.css");
-    #: empty = the built-in dark-tech palette. Validated: bare filename
-    #: only — no paths, no ".." (no-CDN: served from the static dir).
-    theme: str = ""
 
     # --- Database (PostgreSQL 17 + pgvector) ---
     database_url: str = "postgresql+psycopg://reese:reese@localhost:5432/brain_of_reese"
@@ -238,27 +237,6 @@ class Settings(BaseSettings):
     #: separate from ``sources_dir`` (the source checkouts).
     docs_work_dir: str = "~/bor-docs"
 
-    @field_validator("theme", mode="after")
-    @classmethod
-    def _theme_bare_css_filename(cls, v: str) -> str:
-        r"""Phase 62 (A5): the theme is a FILE NAME under
-        ``frontend/assets/themes/``, served from the static dir
-        (no-CDN) — so only a bare lowercase ``.css`` filename is legal
-        (``^[a-z0-9_-]+\.css$``). Anything else (a path, ``..``,
-        uppercase, a missing extension) is a typo that would silently
-        404 at runtime — fail loudly at startup instead, naming the
-        offending value and the allowed shape (the phase-56 fail-loud
-        house style)."""
-        if v == "":
-            return v  # empty = the built-in dark-tech palette
-        if re.fullmatch(r"[a-z0-9_-]+\.css", v) is None:
-            raise ValueError(
-                "theme must be a bare .css filename under "
-                "frontend/assets/themes/ (lowercase letters/digits/"
-                f"'_'/'-', e.g. 'indigo.css') — got {v!r}"
-            )
-        return v
-
     @field_validator("import_extensions")
     @classmethod
     def _import_extensions_known(cls, v: str) -> str: