fix: quality replacement slot floor uses deleted file's score not failed candidate's (#27)

* fix: quality replacement slot floor uses deleted file's score not failed candidate's

When a blur-score replacement deletes a low-quality Frigate file but the
subsequent upload fails, min_quality_score_for_slot was set to candidate_score
(the good file that failed to upload). This filtered out any subsequent
candidate that didn't beat the failed upload, even if it was better than
the file we just deleted — leaving the freed slot unfilled unnecessarily.

The comment on the guard already documented the correct intent: 'require
the next candidate to beat the deleted file's score'. Fix: use target_score
(the deleted file's blur score) as the floor instead of candidate_score.

* chore: bump version to 0.5.4

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "winnow"
-version = "0.5.3"
+version = "0.5.4"
 description = "Selects diverse, high-quality photos from Immich as training data for Frigate face recognition."
 license = "AGPL-3.0-or-later"
 requires-python = ">=3.13"