feat(backend): add GET /api/claims with filter/sort/pagination

backend/src/cyclone/api.py

@@ -417,4 +417,37 @@ def get_batch(batch_id: str) -> Any:
     return json.loads(rec.result.model_dump_json())
 
 
+@app.get("/api/claims")
+def list_claims(
+    batch_id: str | None = Query(None),
+    status: str | None = Query(None),
+    provider_npi: str | None = Query(None),
+    payer: str | None = Query(None),
+    date_from: str | None = Query(None),
+    date_to: str | None = Query(None),
+    sort: str | None = Query(None),
+    order: str = Query("desc"),
+    limit: int = Query(100, ge=1, le=1000),
+    offset: int = Query(0, ge=0),
+) -> dict[str, Any]:
+    common = dict(
+        batch_id=batch_id,
+        status=status,
+        provider_npi=provider_npi,
+        payer=payer,
+        date_from=date_from,
+        date_to=date_to,
+    )
+    items = list(store.iter_claims(
+        sort=sort, order=order, limit=limit, offset=offset, **common,
+    ))
+    total = len(list(store.iter_claims(**common)))
+    return {
+        "items": items,
+        "total": total,
+        "returned": len(items),
+        "has_more": total > offset + len(items),
+    }
+
+
 __all__ = ["app"]