V4.6 Phase 1: deletions and quick wins

Pure remediation; no behavior change. Every item traces to a finding in
docs/architecture_code_review_2026-08-17.md.

Deletions
- Delete app_state.py, which had zero importers and whose get_session_factory
  raised TypeError at runtime [HIGH-01].
- Delete services/transcription.py and point build_prompt_execution imports at
  services/sources.py; drop the store.py compatibility aliases [MED-05].
- Delete ServiceBase.queue and its unparameterized asyncio.Queue [MED-07].
- Delete db/operations.get_next_queued_job, a divergent duplicate [CRIT-01].
- Drop the discarded load_docs parameter from list_jobs [LOW-03].

Config
- Delete worker_retry_backoff_seconds; no backoff behavior existed anywhere, so
  wiring it would have been a new feature [MED-02].
- Wire sqlite_check_same_thread through get_engine. The engine hardcoded the
  setting's own default, so this preserves behavior exactly [MED-02].
- Replace DATABASE_URL in docker-compose.yml with the nested DATABASE__DRIVER /
  DATABASE__PATH names. Settings uses env_nested_delimiter with extra="ignore",
  so DATABASE_URL was silently discarded [MED-10].

UI
- Move the 23KB inline VIBESCRIBE_LOGO_SVG to ui/static/vibescribe_logo.svg and
  load it through a cached read_svg sibling of read_css [MED-09].
- Route the portrait upload failure through error_presenter.show_error [LOW-07].
- Cancel the job detail auto-refresh timer instead of only deactivating it, and
  name its interval constant [LOW-06].

Worker
- Make WorkerNotifier runtime_checkable and validate the resolved object in
  resolve_worker_notifier, which previously returned any non-None attribute
  unchecked [LOW-04].

Docs and lint
- Fix two stale paths in services.instructions.md, one of which pointed at the
  module deleted here [LOW-02].
- ruff check --fix to zero [LOW-01].

Verified: 264 passed, 4 skipped; ruff check clean.

Co-authored-by: Copilot App <[email protected]>

tests/services/test_transcription_external.py

@@ -5,7 +5,7 @@ from pathlib import Path
 
 import pytest
 
-from transcription.services.transcription import transcribe_document_image
+from transcription.services.sources import transcribe_document_image
 
 HAS_OPENROUTER_KEY = bool(os.getenv("OPENROUTER_API_KEY"))
 

tests/test_app.py

@@ -20,6 +20,7 @@ class TestAppFactory:
         app = create_app()
         assert isinstance(app, FastAPI)
 
+
 @pytest.mark.integration
 class TestAppLifespan:
     """Verify startup and shutdown lifecycle behavior."""

tests/test_config.py

@@ -146,7 +146,6 @@ class TestWorkerReliabilitySettings:
     """Verify worker retry settings defaults."""
 
     def test_worker_retry_defaults(self):
-        """worker retry settings default to no retries and no backoff."""
+        """worker retry settings default to no retries."""
         settings = _make_settings()
         assert settings.worker_max_retries == 0
-        assert settings.worker_retry_backoff_seconds == 0.0

tests/ui/test_upload_page.py

@@ -41,4 +41,3 @@ class TestPageRendering:
         assert response.status_code == 200
         assert "Edit Home Page" in response.text
         assert "Homepage markdown" in response.text
-