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/assistant.py

@@ -1,5 +1,5 @@
 # [DEF:backend.src.models.assistant:Module]
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 # @SEMANTICS: assistant, audit, confirmation, chat
 # @PURPOSE: SQLAlchemy models for assistant audit trail and confirmation tokens.
 # @LAYER: Domain
@@ -14,7 +14,7 @@ from .mapping import Base
 
 
 # [DEF:AssistantAuditRecord:Class]
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 # @PURPOSE: Store audit decisions and outcomes produced by assistant command handling.
 # @PRE: user_id must identify the actor for every record.
 # @POST: Audit payload remains available for compliance and debugging.
@@ -33,7 +33,7 @@ class AssistantAuditRecord(Base):
 
 
 # [DEF:AssistantMessageRecord:Class]
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 # @PURPOSE: Persist chat history entries for assistant conversations.
 # @PRE: user_id, conversation_id, role and text must be present.
 # @POST: Message row can be queried in chronological order.
@@ -54,7 +54,7 @@ class AssistantMessageRecord(Base):
 
 
 # [DEF:AssistantConfirmationRecord:Class]
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 # @PURPOSE: Persist risky operation confirmation tokens with lifecycle state.
 # @PRE: intent/dispatch and expiry timestamp must be provided.
 # @POST: State transitions can be tracked and audited.