fix: raise MIN_FACE_WIDTH default from 50 to 90px (8k pixel floor)

50px crops produce ~2,500–4,225 total pixels — well below Frigate's own
camera capture range of 16k–50k px. 90px guarantees ≥8,100 total pixels
even when face margins are fully clipped by image edges.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_config.py

@@ -17,7 +17,7 @@ def test_config_loads_defaults(monkeypatch):
     assert cfg.API_KEY == "test-key"
     assert cfg.OUTPUT_DIR == "./frigate_train"
     assert cfg.YEARS_FILTER == 10
-    assert cfg.MIN_FACE_WIDTH == 50
+    assert cfg.MIN_FACE_WIDTH == 90
     assert cfg.MIN_FACE_COUNT == 0
     assert cfg.BLUR_THRESHOLD == 100.0
     assert cfg.MIN_CONFIDENCE == 0.7