Fix tracker pattern review issues

- Fix TotalCount resolver to dispatch by parent type instead
  of always using the uncategorised banner counter
- Sync MCP tracker_type enum with canonical TrackerType values
- Add validation for UpdateTrackerPatternRequest
- Validate tracker_type on CreateTrackerPatternRequest
- Set LastMatchedAt when creating pattern from detection
- Use COALESCE for SOURCE cursor pagination with NULLs
- Make source nullable in CLI tracker-pattern list

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/server/api/mcp/v1/specification.yaml

@@ -9163,7 +9163,7 @@ components:
           description: Cookie category ID
         tracker_type:
           type: string
-          enum: [COOKIE, LOCAL_STORAGE, SESSION_STORAGE, PIXEL]
+          enum: [COOKIE, LOCAL_STORAGE, SESSION_STORAGE, INDEXED_DB, SCRIPT, IFRAME]
           description: Type of tracker
         pattern:
           type: string
@@ -9689,7 +9689,7 @@ components:
           $ref: "#/components/schemas/GID"
         tracker_type:
           type: string
-          enum: [COOKIE, LOCAL_STORAGE, SESSION_STORAGE, PIXEL]
+          enum: [COOKIE, LOCAL_STORAGE, SESSION_STORAGE, INDEXED_DB, SCRIPT, IFRAME]
         pattern:
           type: string
         match_type: