phase: 93_theme_semantic_completion

All verification is complete. Final report:

**Phase 93 — Theme semantic completion: FINAL VERIFICATION PASS — ALL GREEN**

- Verified full implementation in tree: migration `0016` (8 nullable semantic columns, applied at head), 17-var `BUILTIN_COLORS`/`COLOR_FIELDS`/`effective_settings`, API validation, `#view-theme` State-colors fieldset (17 pickers), `theme.js` FIELDS/PAIRS (5→8), `.page-head` surface panel (6 shell views + doc-edit + shared.html; login card / document sticky header audited as already-surfaced), mock_llm `content: None` fix
- Fixed 2 pre-existing defects (both fail identically on baseline `d4f38ad`, proven via worktree A/B): `test_nav_rename_sources` — expected nav tail missing the phase-91 "Theme" link; `test_stale_ui_copy` — now truncates `saved_chats` before/after (house `test_suggestion_chips` pattern) so the seed-chip contract is deterministic on the shared dev DB (owner's 22 saved chats triggered phase-80 last-3-questions)
- Tests: `uv run pytest --cov=app --cov-report=term-missing` → **1868 passed, app/ 99%** (>90% ✓); `uv run ruff check .` → clean; `uv run pyright` → **0 errors**
- E2E: dedicated `uv run pytest tests/e2e/test_theme_semantic_completion.py -v --no-cov` → **8/8 in isolation** (all-gray 17-color theme: zero residual color on saved-result/Stale/Revoked/Local/tool-call elements, text labels intact, gray heads non-transparent, pre-paint tag, Reset → byte-identical no-tag); 15 theme/header/nav/responsive suites green in isolation; full 85-file combined run: only the 2 fixed pre-existing failures + 1 combined-run artifact (`test_sync_upload_progress`, green in isolation)
- Completion criteria: (1) monochrome E2E ✓ (2) default byte-identical, no `#bor-theme` tag ✓ (3) all page heads on solid surface ✓ (4) suite/coverage/lint/E2E green ✓ (5) phases 01–92 no behavior change ✓ (6) commit left to harness per protocol
- Notable: cleaned stray uvicorn leftovers from prior implementation pass (owner's `--reload` dev server untouched); no deviations from the phase design
- Next pending phase: `94_ls_tree_drilldown`

frontend/shared.html

@@ -140,8 +140,13 @@
          too (no href — guests cannot open documents, the documents
          API is admin-only, phase 16). -->
     <div class="container shared-shell">
-      <h1 id="shared-title">Shared conversation</h1>
-      <p class="shared-note">Shared via Brain of Reese — read-only.</p>
+      <!-- Phase 93 task 03 (TODO.md L3): the head sits on the shared
+           .page-head surface panel — the grid no longer fights the
+           heading text (the h1 + lede were direct shell children). -->
+      <div class="page-head">
+        <h1 id="shared-title">Shared conversation</h1>
+        <p class="shared-note">Shared via Brain of Reese — read-only.</p>
+      </div>
 
       <!-- The invalid / revoked state — ship-hidden; shared.js reveals
            it for a malformed token (no fetch of any kind) and for a