fix(security): fix plugin update logging and config validation leak

- update_plugin: change logger.exception to logger.error in non-except
  branch (logger.exception outside an except block logs useless
  "NoneType: None" traceback)
- update_plugin: remove duplicate logger.exception call in except block
  (was logging the same failure twice)
- save_plugin_config validation: stop logging full plugin_config dict
  (can contain API keys, passwords, tokens) and raw form_data values;
  log only keys and validation errors instead

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/web_interface/errors.py

@@ -214,19 +214,47 @@ class WebInterfaceError:
         
         return cls(
             error_code=error_code,
-            message=str(exception),
+            message=cls._safe_message(error_code),
             details=cls._get_exception_details(exception),
             context=error_context,
             original_error=exception
         )
 
+    @classmethod
+    def _safe_message(cls, error_code: ErrorCode) -> str:
+        """Get a safe, user-facing message for an error code."""
+        messages = {
+            ErrorCode.CONFIG_SAVE_FAILED: "Failed to save configuration",
+            ErrorCode.CONFIG_LOAD_FAILED: "Failed to load configuration",
+            ErrorCode.CONFIG_VALIDATION_FAILED: "Configuration validation failed",
+            ErrorCode.CONFIG_ROLLBACK_FAILED: "Failed to rollback configuration",
+            ErrorCode.PLUGIN_NOT_FOUND: "Plugin not found",
+            ErrorCode.PLUGIN_INSTALL_FAILED: "Failed to install plugin",
+            ErrorCode.PLUGIN_UPDATE_FAILED: "Failed to update plugin",
+            ErrorCode.PLUGIN_UNINSTALL_FAILED: "Failed to uninstall plugin",
+            ErrorCode.PLUGIN_LOAD_FAILED: "Failed to load plugin",
+            ErrorCode.PLUGIN_OPERATION_CONFLICT: "A plugin operation is already in progress",
+            ErrorCode.VALIDATION_ERROR: "Validation error",
+            ErrorCode.SCHEMA_VALIDATION_FAILED: "Schema validation failed",
+            ErrorCode.INVALID_INPUT: "Invalid input",
+            ErrorCode.NETWORK_ERROR: "Network error",
+            ErrorCode.API_ERROR: "API error",
+            ErrorCode.TIMEOUT: "Operation timed out",
+            ErrorCode.PERMISSION_DENIED: "Permission denied",
+            ErrorCode.FILE_PERMISSION_ERROR: "File permission error",
+            ErrorCode.SYSTEM_ERROR: "A system error occurred",
+            ErrorCode.SERVICE_UNAVAILABLE: "Service unavailable",
+            ErrorCode.UNKNOWN_ERROR: "An unexpected error occurred",
+        }
+        return messages.get(error_code, "An unexpected error occurred")
+
     @classmethod
     def _infer_error_code(cls, exception: Exception) -> ErrorCode:
         """Infer error code from exception type."""
         exception_name = type(exception).__name__
         
         if "Config" in exception_name:
-            return ErrorCode.CONFIG_SAVE_FAILED
+            return ErrorCode.CONFIG_LOAD_FAILED
         elif "Plugin" in exception_name:
             return ErrorCode.PLUGIN_LOAD_FAILED
         elif "Permission" in exception_name or "Access" in exception_name:

web_interface/app.py

@@ -11,6 +11,7 @@ from datetime import datetime, timedelta
 sys.path.insert(0, str(Path(__file__).parent.parent))
 
 from src.config_manager import ConfigManager
+from src.exceptions import ConfigError
 from src.plugin_system.plugin_manager import PluginManager
 from src.plugin_system.store_manager import PluginStoreManager
 from src.plugin_system.saved_repositories import SavedRepositoriesManager
@@ -492,7 +493,7 @@ def display_preview_generator():
         parallel = main_config.get('display', {}).get('hardware', {}).get('parallel', 1)
         width = cols * chain_length
         height = rows * parallel
-    except (KeyError, TypeError, ValueError):
+    except (KeyError, TypeError, ValueError, ConfigError):
         width = 128
         height = 64