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/core/migration/test_archive_parser.py

@@ -1,6 +1,6 @@
 # [DEF:backend.tests.core.migration.test_archive_parser:Module]
 #
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 # @PURPOSE: Unit tests for MigrationArchiveParser ZIP extraction contract.
 # @LAYER: Domain
 # @RELATION: VERIFIES -> backend.src.core.migration.archive_parser

backend/tests/core/migration/test_dry_run_orchestrator.py

@@ -1,6 +1,6 @@
 # [DEF:backend.tests.core.migration.test_dry_run_orchestrator:Module]
 #
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 # @PURPOSE: Unit tests for MigrationDryRunService diff and risk computation contracts.
 # @LAYER: Domain
 # @RELATION: VERIFIES -> backend.src.core.migration.dry_run_orchestrator

backend/tests/core/test_git_service_gitea_pr.py

@@ -1,5 +1,5 @@
 # [DEF:backend.tests.core.test_git_service_gitea_pr:Module]
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 # @SEMANTICS: tests, git, gitea, pull_request, fallback
 # @PURPOSE: Validate Gitea PR creation fallback behavior when configured server URL is stale.
 # @LAYER: Domain

backend/tests/core/test_mapping_service.py

@@ -1,6 +1,6 @@
 # [DEF:backend.tests.core.test_mapping_service:Module]
 #
-# @TIER:      STANDARD
+# @COMPLEXITY: 3
 # @PURPOSE:   Unit tests for the IdMappingService matching UUIDs to integer IDs.
 # @LAYER:     Domain
 # @RELATION:  VERIFIES -> backend.src.core.mapping_service

backend/tests/core/test_migration_engine.py

@@ -1,6 +1,6 @@
 # [DEF:backend.tests.core.test_migration_engine:Module]
 #
-# @TIER:      STANDARD
+# @COMPLEXITY: 3
 # @PURPOSE:   Unit tests for MigrationEngine's cross-filter patching algorithms.
 # @LAYER:     Domain
 # @RELATION:  VERIFIES -> backend.src.core.migration_engine