PR 6: Database migration validation - fresh/upgrade test complete

✅ Database Setup:
- Created PostgreSQL kartselldb with kartsell user
- SSH port forward established (localhost:5432 → 178.104.200.7:5432)

✅ DbMigrator Fixes:
- Fixed migration path discovery (AppContext.BaseDirectory fallback)
- Added empty variable dictionary to suppress DbUp preprocessing
- Fixed PostgreSQL dollar quoting conflict ($policy$ → $$)

✅ Migration Results:
- All 21 migrations executed successfully
- Schema versions journal created and tracked
- 21 scripts processed in order, no rollback needed

Status: FRESH DATABASE DEPLOYMENT SUCCESSFUL
- kartselldb fully initialized with v16 schema
- Ready for application startup

Next: Deploy application and run integration tests

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

frontend/src/shared/ui/adapter/tests/uiAdapter.contract.spec.js

@@ -0,0 +1,12 @@
+import { describe, expect, it } from 'vitest';
+import { assertUiAdapterContract, requiredUiAdapterCapabilities } from '../contracts';
+import { nativeUiAdapter } from '../native';
+import { primeVueUiAdapter } from '../primevue';
+describe.each([nativeUiAdapter, primeVueUiAdapter])('UI adapter $descriptor.id', adapter => {
+    it('implements the complete v4 normalized contract', () => {
+        expect(() => assertUiAdapterContract(adapter)).not.toThrow();
+        expect(adapter.descriptor.contractVersion).toBe('4.0');
+        expect(adapter.descriptor.capabilities.size).toBe(requiredUiAdapterCapabilities.length);
+        expect(adapter.descriptor.accessibilityBaseline).toBe('WCAG_2_2_AA_TARGET');
+    });
+});