US01-06: Review Inventory and Duplicates in the Browser (#51)

photo_pipeline/schemas/duplicates.py

@@ -0,0 +1,14 @@
+"""Request contracts for duplicate decisions."""
+
+from __future__ import annotations
+
+from typing import Literal
+
+from pydantic import BaseModel
+
+
+class DecisionRequest(BaseModel):
+    decision: Literal["canonical", "not_duplicate", "deferred"]
+    expected_version: int
+    canonical_asset_id: str | None = None
+    reason: str | None = None