V4.6 Phase 7: drive ty check to zero and add a blocking quality gate [HIGH-06]

Baseline was 207 diagnostics. Two real bugs were hiding in the noise:

- tools/run_destructive_tests.py imported ctypes.wintypes at module scope,
  which raises on non-Windows, and called fcntl unconditionally. The Windows
  and POSIX implementations now live under a module-level sys.platform split.
- tests/ui/test_sources_page.py constructed Source(...) without document_id.

Structural fixes, not suppressions:

- New src/transcription/db/loading.py owns the SQLModel-field to
  QueryableAttribute reinterpretation via orm_attribute()/selectinload()/
  defer(). This removed 42 "# pyright: ignore[reportArgumentType]" comments
  across documents/jobs/people/sources. Its docstring records that
  selectinload(A.b, B.c) is NOT equivalent to the chained form: varargs
  applies the selectin strategy only to the last path element, which under
  lazy="raise" raises InvalidRequestError at render time.
- db/session.py transaction_scope no longer accepts or yields
  AsyncSessionTransaction. No caller ever passed one, sessionmaker.begin()
  yields an AsyncSession, and the dead branch was latently buggy because
  services call .exec(). Cleared 7 workflows.py diagnostics.
- services/registry.py RegistryService is bound by a new RegistryEntry
  Protocol instead of bare SQLModel, so the shared implementation can read
  id/label/normalized_label/is_active. Cleared 9 diagnostics.
- Column expressions in sources.py/jobs.py/test_store.py wrap in sqlmodel
  col(), the idiom already used in registry.py.
- read_source_navigation wraps its literal tuple bounds in literal().
- normalization.py narrows with isinstance(image, TiffImageFile) rather than
  comparing image.format, since tag_v2 is TIFF-only.
- linked_people.render uses @ui.refreshable_method, the NiceGUI API for bound
  methods.
- The OpenRouter capturing client re-raises ResponseNotRead when the response
  stream is not async rather than mis-wrapping it.

Tooling gate:

- New .pre-commit-config.yaml runs ruff check and ty check as blocking hooks.
  No pre-commit config previously existed. Negative-tested: injecting a type
  error fails both hooks.
- The last two "# pyright: ignore" comments (config.py) are removed; ty does
  not honor pyright directives. One "# ty: ignore" remains, in
  tests/test_prompts.py, where the test deliberately assigns to a frozen
  field to assert ValidationError.
- asyncio_default_fixture_loop_scope is pinned to "function" so
  pytest-asyncio behavior does not shift on upgrade.

Verification: ruff check clean, ty check reports 0 diagnostics, 292 passed
and 4 skipped, pre-commit passes and demonstrably fails on a regression, and
tools/run_destructive_tests.py runs on Windows.

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

tests/test_v42_evidence.py

@@ -10,6 +10,7 @@ from uuid import uuid4
 
 import httpx
 import pytest
+from pydantic import JsonValue
 
 from transcription.benchmarking import EditorialAssessment
 from transcription.benchmarking import score_transcription
@@ -33,6 +34,18 @@ from transcription.services.sources import TranscriptionError
 from transcription.services.sources import transcribe_document_image
 
 
+def _json_object(value: JsonValue) -> dict[str, JsonValue]:
+    """Narrow a JSON export member to an object, asserting the export shape."""
+    assert isinstance(value, dict)
+    return value
+
+
+def _json_array(value: JsonValue) -> list[JsonValue]:
+    """Narrow a JSON export member to an array, asserting the export shape."""
+    assert isinstance(value, list)
+    return value
+
+
 class _ChunkedAsyncStream(httpx.AsyncByteStream):
     def __init__(self, chunks: list[bytes]):
         self._chunks = chunks
@@ -261,9 +274,9 @@ async def test_attempts_are_append_only_and_exported_with_integrity(default_sess
         )
     )
     export = await sources.build_evidence_export(source_id=source.id)
-    assert export["source"]["digest_sha256"] == "a" * 64
-    assert [item["attempt_number"] for item in export["attempts"]] == [1, 2]
-    assert export["artifacts"][0]["id"] == str(artifact.id)
+    assert _json_object(export["source"])["digest_sha256"] == "a" * 64
+    assert [_json_object(item)["attempt_number"] for item in _json_array(export["attempts"])] == [1, 2]
+    assert _json_object(_json_array(export["artifacts"])[0])["id"] == str(artifact.id)
     assert "file_path" not in json.dumps(export)
     with pytest.raises(JobDeleteBlockedError):
         await jobs.delete_job_with_guardrails(job_id=job.id)