phase: 190_app_name_settings_fix

All gates re-verified green. Report:

- **Verified (all 4 tasks already complete; this was the final pass):** `effective_settings` resolves the 3 brand strings panel-row → tab-row → env (`applied_override_keys`, presence-not-value); `PUT /api/ui-settings` ignores string body fields; Theme-tab form is colors-only (17 pickers, no `#theme-app-name`/`#theme-placeholder`/`#theme-footer`); the ONE shared `applyBrandFromConfig` re-applies title/`.brand-text`/footer/placeholder after a panel save-reset and a tab save-reset; boot path byte-identical (single `/api/config`).
- **Completion criteria:**
  - strings order panel→tab→env, both branches — ✅ `tests/unit/test_theming.py::test_effective_app_name_prefers_settings_panel_row_over_ui_settings_row`, `..._fall_back_to_ui_settings_row_without_panel_row`, `..._per_field_panel_then_tab_then_env`, `..._ignore_panel_rows_when_the_overlay_is_off`
  - PUT ignores string fields + no 3 inputs in the tab — ✅ `tests/integration/test_ui_settings_api.py::test_put_ignores_string_fields_in_body` (+2) and the E2E `test_theme_tab_dom_is_colors_only`
  - live apply without reload + incident regression — ✅ `tests/e2e/test_app_name_settings_fix.py` tests 1–4
  - byte-identical boot, no double-apply — ✅ `tests/unit/test_brand_live.py` markers + E2E "exactly one /api/config"
  - suite green, coverage >90%, ruff+pyright clean — ✅
  - no behavior change in prior phases — ✅ (palette, phase-168 panel, env fallback suites all green)
  - atomic commit — **left to the harness** (pipeline rule overrides per-phase committing; no git write run)
- **Gates:** `uv run pytest --cov=app --cov-report=term-missing` → **4630 passed, TOTAL 6941 16 99%**, exit 0 · `uv run pytest tests/e2e/test_app_name_settings_fix.py -v --no-cov` → **6 passed** in isolation · regression E2E (isolated, one process each, all exit 0): `test_smoke` `test_configurable_brand` `test_admin_theme_tab` `test_theme_save_and_coverage` `test_theme_semantic_completion` `test_themed_favicon` `test_dark_tech_theme` `test_admin_settings_panel` `test_admin_settings_layout` `test_settings_mobile_value_width` · `uv run ruff check .` → All checks passed · `uv run pyright` → 0 errors.
- **Documentation:** README — fixed "saving one repaints *every* open page" (only the open document repaints; other pages on next load) and a broken paragraph wrap in *Customizing the look*; AGENTS.md rule 16 — `test_chunks_hnsw_recall.py` now described accurately (index paths forced with `enable_seqscan`/`indexonlyscan`/`bitmapscan` off, unforced plan asserted only on a pristine relation); `tests/unit/test_theme_frontend.py` — two stale section headers ("20 form fields"/"20 inputs" → 17 color). No AGENTS.md settings-overlay/resolution-order clause exists, so per the phase none was added. Full env-var cross-check (`BOR_*` in `app/config.py` vs README) → 0 gaps; 0 missing file references.
- **Notable:** the working tree also carries this phase's flake hardening of the phase-188 `tests/integration/test_chunks_hnsw_recall.py` (verified legit and green). Live infra untouched; shared DB left clean (0 `app_settings`, 0 `ui_settings`). **Flagged, not changed:** `settings_overlay.applied_override_keys` lets a `ProgrammingError` (missing `app_settings`) propagate from public `GET /api/config`, where `load_overrides` deliberately fails soft — only reachable on an un-migrated (0027) DB, outside this phase's pinned A1 semantics, so left for the owner to rule on rather than silently deviating.
- **Next pending phase:** `191_source_name_labels_tags`.

tests/e2e/test_theme_semantic_completion.py

@@ -467,11 +467,11 @@ def test_tab_ui_save_gray_roundtrip(page: Page, app_url: str, db_ready: None) ->
     # feed the PUT body, the live preview, and the refetch).
     for field in COLOR_FIELDS:
         page.fill(f"#theme-{field.replace('_', '-')}", GRAY[field])
-    # The 3 strings stay default (untouched — they hold the effective
-    # template defaults the module server pins).
+    # The tab has no string inputs (phase 190, A1) — the 3 brand
+    # strings are the Settings panel's, so nothing here can touch them.
 
-    # Capture the PUT body the form builds (the wiring proof: all 17
-    # grays ride the wire together with the 3 default strings).
+    # Capture the PUT body the form builds (the wiring proof: the 17
+    # grays ride the wire and NOTHING else — no string key, phase 190).
     captured: dict[str, Any] = {}
 
     def handle(route: Route) -> None:
@@ -498,11 +498,14 @@ def test_tab_ui_save_gray_roundtrip(page: Page, app_url: str, db_ready: None) ->
     # hidden (it re-checks the saved state on the save's refetch).
     expect(page.locator("#theme-contrast")).to_be_hidden()
 
-    # The PUT carried every field: the 17 grays + the 3 default strings
-    # (the strings were never touched, so they ride at their defaults).
+    # The PUT carried the 17 grays and NOTHING else (phase 190, A1:
+    # the brand strings left the tab's body — an old client's save can
+    # no longer re-bake one and shadow the Settings panel).
     body = captured.get("body")
     assert isinstance(body, dict), "the Save PUT was not captured (route hook?)"
-    assert body == {**GRAY, **defaults}, f"unexpected PUT body: {body}"
+    assert body == GRAY, f"unexpected PUT body: {body}"
+    for field in defaults:
+        assert field not in body, f"{field} must never ride the tab's PUT body"
 
     # The inputs re-populate to the SAVED (effective) grays (the
     # save's refetch is the canonical state)…