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/models/dashboard.py

@@ -1,5 +1,5 @@
 # [DEF:backend.src.models.dashboard:Module]
-# @TIER:      STANDARD
+# @COMPLEXITY: 3
 # @SEMANTICS: dashboard, model, metadata, migration
 # @PURPOSE:   Defines data models for dashboard metadata and selection.
 # @LAYER:     Model
@@ -9,7 +9,7 @@ from pydantic import BaseModel
 from typing import List
 
 # [DEF:DashboardMetadata:Class]
-# @TIER: TRIVIAL
+# @COMPLEXITY: 1
 # @PURPOSE: Represents a dashboard available for migration.
 class DashboardMetadata(BaseModel):
     id: int
@@ -19,7 +19,7 @@ class DashboardMetadata(BaseModel):
 # [/DEF:DashboardMetadata:Class]
 
 # [DEF:DashboardSelection:Class]
-# @TIER: TRIVIAL
+# @COMPLEXITY: 1
 # @PURPOSE: Represents the user's selection of dashboards to migrate.
 class DashboardSelection(BaseModel):
     selected_ids: List[int]