refactor(semantics): migrate legacy @TIER to @COMPLEXITY annotations

- Replaced @TIER: TRIVIAL with @COMPLEXITY: 1
- Replaced @TIER: STANDARD with @COMPLEXITY: 3
- Replaced @TIER: CRITICAL with @COMPLEXITY: 5
- Manually elevated specific critical/complex components to levels 2 and 4
- Ignored legacy, specs, and node_modules directories
- Updated generated semantic map

backend/src/core/task_manager/cleanup.py

@@ -1,5 +1,5 @@
 # [DEF:TaskCleanupModule:Module]
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 # @SEMANTICS: task, cleanup, retention, logs
 # @PURPOSE: Implements task cleanup and retention policies, including associated logs.
 # @LAYER: Core
@@ -12,7 +12,7 @@ from ..config_manager import ConfigManager
 
 # [DEF:TaskCleanupService:Class]
 # @PURPOSE: Provides methods to clean up old task records and their associated logs.
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 class TaskCleanupService:
     # [DEF:__init__:Function]
     # @PURPOSE: Initializes the cleanup service with dependencies.