phase: 100_page_width_consistency

**Phase 100 — final verification pass: all green.**

- Verified the shipped CSS contract directly: `--chat-column: 72rem` in `:root`; 0 literal `max-width: 46rem`; no `@media (min-width: 1500px)` block; exactly 4 token-capped reading columns; tuning/theme/doc-edit shells cap-free, structurally `.sources-shell`; `mock_llm.py` diff is comment-only.
- Defect found & fixed (phase-93 suite): `test_theme_semantic_completion.py::test_reset_removes_tag_byte_identical` raced theme.js's post-PUT refetch — it asserted the `#bor-theme` tag was gone right after the result line, but tag removal lands in the reconcile after the re-fetch (failed ~1 in 5 runs after `test_chat_rag`, reproduced). Fixed with an auto-waiting `expect(...).to_have_count(0)` (settled-state wait, the file's existing house pattern). 6/6 clean on the repro loop after.
- Tests/lint/coverage: `uv run pytest --cov=app --cov-report=term-missing` → 2052 passed, **99%** on `app/`; `uv run ruff check .` + `uv run pyright` → 0 errors.
- E2E in isolation (all passed): `test_wide_desktop_column.py` 3 (the phase suite — chat==tuning==theme==RAG ±4px at 1280 & 1920, ≈1152px; shared ≈1152px; standalone doc ≈1112px; modal unchanged ≈1100px; 360px overflow-free), `test_ui_customization` 4, `test_admin_theme_tab` 5, `test_document_viewer` 7, `test_save_share_ux` 5, `test_sticky_navbar` 3, `test_markdown_tables` 6, `test_responsive_polish` 7, `test_chat_rag` 3, `test_theme_semantic_completion` 8.
- Completion criteria: ① measured 72rem everywhere (≥~1200px, ±4px) + full-width below + 360px clean — **PASS** (E2E); ② zero 46rem rules / no 1500px block / four token selectors — **PASS** (grep + unit pins); ③ B4 byte-identical no-op + mobile squeeze — **PASS** (theme + responsive suites green); ④ full suite / coverage / lint — **PASS**; ⑤ atomic commit — left to the harness per executor protocol (all changes in the working tree, uncommitted).
- Deviations: none from phase decisions; only change in this pass is the race fix above (test-only, behavior unchanged).
- Next pending phase: `98_sync_summary_visibility` (numeric order in `todo/`; also pending: 99, 101–105).

tests/unit/test_doc_edit_screen.py

@@ -10,8 +10,9 @@ without a browser:
 
 * the house shell (AGENTS.md rule 5 + the login.html/shared.html
   minimal-flow-page lineage): skip-link, the SLIM header (brand +
-  "Back to chat" — no nav), the 46rem base column (hard-coded — a form
-  column, NOT ``--chat-column``), the ``container`` frame;
+  "Back to chat" — no nav), the full 72rem container (the phase-59
+  form-column cap is retired — owner instruction 2026-09-12), the
+  ``container`` frame;
 * the form contract: ``#draft-title`` / ``#draft-path`` /
   ``#draft-body`` with visible labels, ``#push-doc-btn`` (the exact
   "Push to docs branch" copy) + the back link, ``#push-status``
@@ -455,21 +456,25 @@ def test_trim_git_detail_behavior_is_pinned_by_the_markers() -> None:
 # ---------- styles.css: the new classes ----------
 
 
-def test_doc_edit_shell_is_the_hardcoded_46rem_column() -> None:
-    """.doc-edit-shell: the 46rem base column — HARD-CODED 46rem (a
-    form column, not a reading column — it must NOT ride
-    --chat-column, so phase 58's wide-desktop doubling never stretches
-    the form), centered, a flex column on the container frame."""
+def test_doc_edit_shell_rides_the_full_container() -> None:
+    """.doc-edit-shell: the full 72rem container (owner instruction
+    2026-09-12 — the phase-59 form-column cap is superseded): no
+    max-width, no margin-inline (the .container ancestor centers), a
+    flex column on the container frame."""
     css = _css()
     block = re.search(r"\.doc-edit-shell \{([\s\S]*?)\n\}", css)
     assert block, "styles.css must style .doc-edit-shell"
     body = block.group(1)
-    assert "max-width: 46rem" in body, "the 46rem base column (hard-coded)"
+    assert "max-width" not in body, (
+        "no cap — the shell rides the .container's 72rem frame"
+    )
     assert "--chat-column" not in body, (
-        "the form column does not ride --chat-column (phase 58 must "
-        "not stretch it)"
+        "the shell rides the .container frame, not the reading-column "
+        "token"
+    )
+    assert "margin-inline" not in body, (
+        "the .container ancestor centers (no shell-level centering)"
     )
-    assert "margin-inline: auto" in body
     assert "flex-direction: column" in body