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/tests/test_task_persistence.py

@@ -3,7 +3,7 @@
 # @PURPOSE: Unit tests for TaskPersistenceService.
 # @LAYER: Test
 # @RELATION: TESTS -> TaskPersistenceService
-# @TIER: CRITICAL
+# @COMPLEXITY: 5
 # @TEST_DATA: valid_task -> {"id": "test-uuid-1", "plugin_id": "backup", "status": "PENDING"}
 
 # [SECTION: IMPORTS]
@@ -22,7 +22,7 @@ from src.core.task_manager.models import Task, TaskStatus, LogEntry
 
 # [DEF:TestTaskPersistenceHelpers:Class]
 # @PURPOSE: Test suite for TaskPersistenceService static helper methods.
-# @TIER: CRITICAL
+# @COMPLEXITY: 5
 class TestTaskPersistenceHelpers:
 
     # [DEF:test_json_load_if_needed_none:Function]
@@ -111,7 +111,7 @@ class TestTaskPersistenceHelpers:
 
 # [DEF:TestTaskPersistenceService:Class]
 # @PURPOSE: Test suite for TaskPersistenceService CRUD operations.
-# @TIER: CRITICAL
+# @COMPLEXITY: 5
 # @TEST_DATA: valid_task -> {"id": "test-uuid-1", "plugin_id": "backup", "status": "PENDING"}
 class TestTaskPersistenceService: