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/connection.py

@@ -1,6 +1,6 @@
 # [DEF:backend.src.models.connection:Module]
 #
-# @TIER: TRIVIAL
+# @COMPLEXITY: 1
 # @SEMANTICS: database, connection, configuration, sqlalchemy, sqlite
 # @PURPOSE:   Defines the database schema for external database connection configurations.
 # @LAYER:     Domain
@@ -16,7 +16,7 @@ import uuid
 # [/SECTION]
 
 # [DEF:ConnectionConfig:Class]
-# @TIER: TRIVIAL
+# @COMPLEXITY: 1
 # @PURPOSE: Stores credentials for external databases used for column mapping.
 class ConnectionConfig(Base):
     __tablename__ = "connection_configs"