refactor(BA-5837): align cache-aware admin_repo with Updater/Purger pattern

The Valkey cache wrapper added in this PR re-introduced the
`(key, spec)` and `(key)` signatures on `db_source.update` /
`db_source.purge`. Switch the cache-aware admin_repository over to
the Updater/Purger pattern from BA-5827 while keeping the merged-
view cache-invalidation hooks intact.

Also rename the residual `extra_config` / `extraConfig` references in
the GQL types and schema dump to `config` for consistency with the
column rename.

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

Author: jopemachine

docs/manager/graphql-reference/supergraph.graphql

@@ -199,7 +199,7 @@ input AdminAppConfigFragmentItemInput
   key: AppConfigFragmentKeyInput!
 
   """Raw configuration payload."""
-  extraConfig: JSON!
+  config: JSON!
 }
 
 """Added in UNRELEASED. Per-item input for admin bulk create / update."""
@@ -1082,7 +1082,7 @@ type AppConfigFragment
   name: String!
 
   """Raw configuration payload, or null."""
-  extraConfig: JSON
+  config: JSON
 
   """Creation timestamp."""
   createdAt: DateTime!
@@ -11568,7 +11568,7 @@ input MyAppConfigFragmentItemInput
   name: String!
 
   """Raw configuration payload."""
-  extraConfig: JSON!
+  config: JSON!
 }
 
 """

docs/manager/graphql-reference/v2-schema.graphql

@@ -151,7 +151,7 @@ input AdminAppConfigFragmentItemInput {
   key: AppConfigFragmentKeyInput!
 
   """Raw configuration payload."""
-  extraConfig: JSON!
+  config: JSON!
 }
 
 """Added in UNRELEASED. Per-item input for admin bulk create / update."""
@@ -762,7 +762,7 @@ type AppConfigFragment {
   name: String!
 
   """Raw configuration payload, or null."""
-  extraConfig: JSON
+  config: JSON
 
   """Creation timestamp."""
   createdAt: DateTime!
@@ -7450,7 +7450,7 @@ input MyAppConfigFragmentItemInput {
   name: String!
 
   """Raw configuration payload."""
-  extraConfig: JSON!
+  config: JSON!
 }
 
 """

src/ai/backend/manager/api/gql/app_config_fragment/types/bulk_inputs.py

@@ -46,7 +46,7 @@
 )
 class AdminAppConfigFragmentItemInputGQL(PydanticInputMixin[AdminItemInputDTO]):
     key: AppConfigFragmentKeyInputGQL = gql_field(description="Natural-key identifier.")
-    extra_config: dict[str, Any] = gql_field(description="Raw configuration payload.")
+    config: dict[str, Any] = gql_field(description="Raw configuration payload.")
 
 
 @gql_pydantic_input(
@@ -91,7 +91,7 @@ class AdminBulkPurgeAppConfigFragmentInputGQL(PydanticInputMixin[AdminBulkPurgeI
 )
 class MyAppConfigFragmentItemInputGQL(PydanticInputMixin[MyItemInputDTO]):
     name: str = gql_field(description="Policy name.")
-    extra_config: dict[str, Any] = gql_field(description="Raw configuration payload.")
+    config: dict[str, Any] = gql_field(description="Raw configuration payload.")
 
 
 @gql_pydantic_input(

src/ai/backend/manager/api/gql/app_config_fragment/types/node.py

@@ -41,8 +41,6 @@ class AppConfigFragmentGQL(PydanticOutputMixin[AppConfigFragmentNode]):
     scope_type: AppConfigScopeType = gql_field(description="Scope type.")
     scope_id: str = gql_field(description="Scope id.")
     name: str = gql_field(description="Policy name (FK to app_config_policies).")
-    extra_config: dict[str, Any] | None = gql_field(
-        description="Raw configuration payload, or null."
-    )
+    config: dict[str, Any] | None = gql_field(description="Raw configuration payload, or null.")
     created_at: datetime = gql_field(description="Creation timestamp.")
     updated_at: datetime | None = gql_field(description="Last update timestamp.")

src/ai/backend/manager/repositories/app_config_fragment/admin_repository.py

@@ -116,19 +116,39 @@ async def update(
         key: AppConfigFragmentKey,
         config: Mapping[str, Any],
     ) -> AppConfigFragmentData:
-        """Update a fragment by natural key. Raises
-        ``AppConfigFragmentNotFound`` when missing."""
-        spec = AppConfigFragmentUpdaterSpec(extra_config=extra_config)
-        result = await self._db_source.update(key, spec)
+        """Update a fragment by natural key. Resolves the natural key
+        to the row's UUID, builds an ``Updater``, and delegates to the
+        DB source. Raises :class:`AppConfigFragmentNotFound` when the
+        row is missing (or vanishes between resolve and write)."""
+        pk_value = await self._db_source.resolve_pk_by_key(key)
+        if pk_value is None:
+            raise _missing(key)
+        updater: Updater[AppConfigFragmentRow] = Updater(
+            spec=AppConfigFragmentUpdaterSpec(config=config),
+            pk_value=pk_value,
+        )
+        result = await self._db_source.update(updater)
+        if result is None:
+            raise _missing(key)
         await self._invalidate(key)
         return result
 
     @app_config_fragment_admin_repository_resilience.apply()
     async def purge(self, key: AppConfigFragmentKey) -> bool:
-        result = await self._db_source.purge(key)
-        if result:
+        """Delete a fragment by natural key. Resolves the natural key,
+        builds a ``Purger``, delegates to the DB source, and (on a
+        real removal) invalidates the merged-view cache."""
+        pk_value = await self._db_source.resolve_pk_by_key(key)
+        if pk_value is None:
+            return False
+        purger: Purger[AppConfigFragmentRow] = Purger(
+            row_class=AppConfigFragmentRow,
+            pk_value=pk_value,
+        )
+        removed = await self._db_source.purge(purger)
+        if removed:
             await self._invalidate(key)
-        return result
+        return removed
 
     async def _invalidate(self, key: AppConfigFragmentKey) -> None:
         if self._cache_source is None: