test(allowlist): unique image paths in coverage tests (CI fix)

The new coverage tests' sequential shas (c{i:063d}) share their first 8 chars,
so deriving the image path from sha[:8] collided on uq_image_record_path. Use
the full sha in the path. Same hardening for test_api_suggestions._img.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XCUHUGQLrBrkgyk1t49kpX

tests/test_api_suggestions.py

@@ -18,7 +18,7 @@ async def _img(db, preds, sha="s" * 64):
     from tests._prediction_helpers import seed_predictions
 
     img = ImageRecord(
-        path=f"/images/{sha[:8]}.jpg", sha256=sha, size_bytes=1,
+        path=f"/images/{sha}.jpg", sha256=sha, size_bytes=1,
         mime="image/jpeg", width=1, height=1,
         origin="imported_filesystem", integrity_status="unknown",
     )

tests/test_ml_allowlist.py

@@ -18,7 +18,9 @@ pytestmark = pytest.mark.integration
 async def _make_image(db, sha: str = "x" * 64):
     from backend.app.models import ImageRecord
     img = ImageRecord(
-        path=f"/images/{sha[:8]}.jpg", sha256=sha, size_bytes=1,
+        # Full sha in the path — the first 8 chars collide for sequential
+        # shas like c{i:063d}, and path is UNIQUE (uq_image_record_path).
+        path=f"/images/{sha}.jpg", sha256=sha, size_bytes=1,
         mime="image/jpeg", width=1, height=1,
         origin="imported_filesystem", integrity_status="unknown",
     )