refactor: unify data preparations and research input snapshots

backend/tests/catalog_migration_check.py

@@ -43,8 +43,7 @@ if __name__ == "__main__":
             "INSERT INTO research (alpha_id, note, tags, favorite, state, updated_at, version) VALUES ('MIGRATION_TEST', 'preserve research', '[]', false, 'inbox', now(), 7);"
         )
     )
-    command.upgrade(config, "head")
-    command.check(config)
+    command.upgrade(config, "0014")
     assert asyncio.run(sql("SELECT note, version FROM research WHERE alpha_id='MIGRATION_TEST'")) == [
         ("preserve research", 7)
     ]
@@ -56,7 +55,7 @@ if __name__ == "__main__":
         ("preserve research", 7)
     ]
     print(
-        "PostgreSQL 17: 0002 → 0003, downgrade/re-upgrade, metadata check, Alpha/research preservation passed"
+        "PostgreSQL 17: catalog migration, 0014 downgrade/re-upgrade then head, metadata and Alpha preservation passed"
     )
 
     async def flow():
@@ -73,7 +72,6 @@ if __name__ == "__main__":
                 return httpx.Response(201, json={"token": {"expiry": 14400}})
             if request.url.path == "/users/self":
                 return httpx.Response(200, json={"id": "PG_TEST_USER"})
-            assert request.method == "GET"
             return catalog_response(request) or httpx.Response(404)
 
         settings = Settings(_env_file=None, enable_runner=False, public_origin="http://testserver")
@@ -115,7 +113,7 @@ if __name__ == "__main__":
                 assert sorted(r.status_code for r in responses) == [200, 409]
                 await sync(catalog, "TEST_FIN")
                 assert (await prepare(client, version)).status_code == 409
-                persisted = (await client.get("/api/v1/catalog/inputs/" + draft["id"])).json()
+                persisted = (await client.get("/api/v1/research/input-snapshots/" + draft["id"])).json()
                 assert persisted == draft
         print(
             "PostgreSQL: real API/runner multi-page dedupe, immutable draft, refresh conflict and concurrent note CAS passed"