fix(plugins): skip update for local-only plugins instead of failing (#354)

Adds a local_only flag to the starlark-apps manifest so the update
endpoint returns a skipped status rather than recording a false failure
when the plugin has no git repo and no registry entry.

Co-authored-by: Chuck <chuck@example.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

plugin-repos/starlark-apps/manifest.json

@@ -22,5 +22,6 @@
     "Pillow>=10.0.0",
     "PyYAML>=6.0",
     "requests>=2.31.0"
-  ]
+  ],
+  "local_only": true
 }

web_interface/blueprints/api_v3.py

@@ -2687,6 +2687,16 @@ def update_plugin():
                 with open(manifest_path, 'r', encoding='utf-8') as f:
                     manifest = json.load(f)
                     current_last_updated = manifest.get('last_updated')
+                if manifest.get('local_only'):
+                    logger.debug("Skipping update for local-only plugin: %s", plugin_id)
+                    if api_v3.operation_history:
+                        api_v3.operation_history.record_operation(
+                            "update",
+                            plugin_id=plugin_id,
+                            status="skipped",
+                            details={"reason": "local_only"}
+                        )
+                    return success_response(message=f'Plugin {plugin_id} is managed locally and does not receive registry updates')
             except Exception as e:
                 logger.debug("Could not read local manifest for plugin: %s", e)