fix: resolve the community schema version at runtime

- write through get_schema_path() instead of a literal v1 filename
- drop the unreferenced SCHEMA_PATH backwards-compatibility shim
- widen the community PR trigger to schemas/** so a version bump still fires it

Generated-by: Claude Opus 5 <noreply@anthropic.com>

.github/workflows/update-community-prs.yaml

@@ -5,7 +5,7 @@ on:
     branches: [main]
     paths:
       - 'community/**'
-      - 'schemas/community_submission.v1.schema.json'
+      - 'schemas/**'
 
 permissions:
   contents: write