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/core/migration/__init__.py

@@ -1,5 +1,5 @@
 # [DEF:backend.src.core.migration.__init__:Module]
-# @TIER: TRIVIAL
+# @COMPLEXITY: 1
 # @SEMANTICS: migration, package, exports
 # @PURPOSE: Namespace package for migration pre-flight orchestration components.
 # @LAYER: Core

backend/src/core/migration/archive_parser.py

@@ -1,5 +1,5 @@
 # [DEF:backend.src.core.migration.archive_parser:Module]
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 # @SEMANTICS: migration, zip, parser, yaml, metadata
 # @PURPOSE: Parse Superset export ZIP archives into normalized object catalogs for diffing.
 # @LAYER: Core

backend/src/core/migration/dry_run_orchestrator.py

@@ -1,12 +1,12 @@
 # [DEF:backend.src.core.migration.dry_run_orchestrator:Module]
-# @TIER: STANDARD
+# @COMPLEXITY: 3
 # @SEMANTICS: migration, dry_run, diff, risk, superset
 # @PURPOSE: Compute pre-flight migration diff and risk scoring without apply.
 # @LAYER: Core
-# @RELATION: DEPENDS_ON -> backend.src.core.superset_client
-# @RELATION: DEPENDS_ON -> backend.src.core.migration_engine
-# @RELATION: DEPENDS_ON -> backend.src.core.migration.archive_parser
-# @RELATION: DEPENDS_ON -> backend.src.core.migration.risk_assessor
+# @RELATION: DEPENDS_ON ->[backend.src.core.superset_client.SupersetClient]
+# @RELATION: DEPENDS_ON ->[backend.src.core.migration_engine.MigrationEngine]
+# @RELATION: DEPENDS_ON ->[backend.src.core.migration.archive_parser.MigrationArchiveParser]
+# @RELATION: DEPENDS_ON ->[backend.src.core.migration.risk_assessor]
 # @INVARIANT: Dry run is informative only and must not mutate target environment.
 
 from datetime import datetime, timezone

backend/src/core/migration/risk_assessor.py

@@ -1,5 +1,5 @@
 # [DEF:backend.src.core.migration.risk_assessor:Module]
-# @TIER: CRITICAL
+# @COMPLEXITY: 5
 # @SEMANTICS: migration, dry_run, risk, scoring, preflight
 # @PURPOSE: Compute deterministic migration risk items and aggregate score for dry-run reporting.
 # @LAYER: Domain