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`.

app/core/settings_overlay.py

@@ -32,6 +32,12 @@ pre-migration deployment is a normal state); any other DB failure is
 one WARNING per process naming the exception class ("settings
 overrides unavailable — env values in effect"). Both "once per process"
 guards are module-level flags, reset by :func:`reset_state_for_tests`.
+
+Phase 190 (task 02) adds the one question another resolver asks this
+table: :func:`applied_override_keys` — "which keys does the Settings
+panel own right now?" (the brand-string ownership order in
+:func:`app.core.theming.effective_settings`). It reads on the CALLER's
+session, so answering it costs no second engine and never a stale view.
 """
 from __future__ import annotations
 
@@ -45,6 +51,7 @@ from pydantic import ValidationError
 from sqlalchemy import create_engine, text
 from sqlalchemy.engine import Engine
 from sqlalchemy.exc import ProgrammingError, SQLAlchemyError
+from sqlalchemy.orm import Session
 from sqlalchemy.pool import NullPool
 
 from app.config import Settings
@@ -125,6 +132,38 @@ def load_overrides() -> dict[str, str]:
         return {}
 
 
+def applied_override_keys(session: Session) -> frozenset[str]:
+    """The ``app_settings`` keys IN EFFECT right now — phase 190 task 02.
+
+    :func:`app.core.theming.effective_settings` needs exactly this to
+    answer "does the admin's Settings panel own this brand string?" (A1:
+    the panel row beats the Theme-tab row, and only a REAL row counts —
+    comparing values would mis-read a panel row that happens to equal
+    the env value, the exact shadow the phase-190 incident is).
+
+    Read on the CALLER's session — one ``SELECT`` on a connection the
+    caller already holds, transactionally consistent with the
+    ``ui_settings`` read beside it (a cross-request memo of the key set
+    would go stale the moment a row is written outside the panel and
+    could re-shadow a just-saved value). The resolver calls this ONCE
+    per resolution and tests the three string fields for membership, so
+    a resolution costs no second query per field.
+
+    The kill switch (``BOR_SETTINGS_DB``, D6) short-circuits before any
+    read — with the overlay off no row is in effect, and the Theme-tab
+    row keeps its phase-91 fallback. A non-overridable key (LOCKED A3)
+    and an orphan row (a field a later release removed) are never
+    "in effect": :func:`merge` drops them, so they must not win here
+    either.
+    """
+    if not enabled():
+        return frozenset()
+    keys = session.execute(text("SELECT key FROM app_settings")).scalars().all()
+    return frozenset(
+        key for key in keys if key in Settings.model_fields and CATALOG[key].overridable
+    )
+
+
 def _coerce(field_name: str, raw: str) -> Any:
     """Coerce one env-native string row value for the candidate set.