fix(test): sidecar idempotency needs phash_threshold=0 (orthogonal splits collapse at default)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_sidecar_import.py

@@ -92,13 +92,17 @@ def test_sidecar_creates_provenance(importer, import_layout):
 
 def test_reimport_same_post_idempotent(importer, import_layout):
     import_root, _ = import_layout
+    # Threshold 0: only an exact phash match collapses. Orthogonal splits
+    # still sit within the default Hamming-10 at 64-bit, so without this
+    # the 2nd image would be skipped as a near-dup (phash dedup working).
+    importer.settings.phash_threshold = 0
     payload = {"category": "patreon", "id": 777, "title": "P"}
     m1 = import_root / "Bob" / "p1.jpg"
     _split(m1, "v")
     _sidecar(m1, payload)
     importer.import_one(m1)
     m2 = import_root / "Bob" / "p2.jpg"
-    _split(m2, "h")            # structurally distinct → not a phash dup
+    _split(m2, "h")            # distinct phash; threshold 0 → both import
     _sidecar(m2, payload)
     r2 = importer.import_one(m2)
     assert r2.status == "imported"