refactor: move json/ to top-level, remove frontend/, update workflows

- Move frontend/public/json/ to json/ (top-level)
- Update all workflow path references to json/
- Delete frontend-cicd.yml workflow
- Delete frontend/ directory entirely
- Clean up .gitattributes (remove frontend entries)

.github/workflows/update-github-versions.yml

@@ -11,7 +11,7 @@ permissions:
   pull-requests: write
 
 env:
-  VERSIONS_FILE: frontend/public/json/github-versions.json
+  VERSIONS_FILE: json/github-versions.json
 
 jobs:
   update-github-versions:
@@ -58,7 +58,7 @@ jobs:
           echo ""
           echo "=== Scanning JSON files for slugs ==="
 
-          for json_file in frontend/public/json/*.json; do
+          for json_file in json/*.json; do
             [[ ! -f "$json_file" ]] && continue
 
             # Skip non-app JSON files
@@ -200,7 +200,7 @@ jobs:
               --body "This PR updates version information from GitHub releases.
 
           ## How it works
-          1. Scans all JSON files in \`frontend/public/json/\` for slugs
+          1. Scans all JSON files in \`json/\` for slugs
           2. Finds corresponding \`install/{slug}-install.sh\` scripts
           3. Extracts \`fetch_and_deploy_gh_release\` calls
           4. Fetches latest (or pinned) version from GitHub