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/status/DataFreshnessBadge.vue.js

@@ -0,0 +1,25 @@
+import { computed } from 'vue';
+const props = defineProps();
+const ageMinutes = computed(() => Math.max(0, (Date.now() - new Date(props.asOf).getTime()) / 60_000));
+const stale = computed(() => ageMinutes.value > props.staleAfterMinutes);
+const __VLS_ctx = {
+    ...{},
+    ...{},
+    ...{},
+    ...{},
+};
+let __VLS_components;
+let __VLS_intrinsics;
+let __VLS_directives;
+__VLS_asFunctionalElement1(__VLS_intrinsics.span, __VLS_intrinsics.span)({
+    'aria-label': (__VLS_ctx.stale ? '데이터 지연' : '데이터 최신'),
+    'data-status': (__VLS_ctx.stale ? 'stale' : 'fresh'),
+});
+(__VLS_ctx.stale ? 'STALE' : 'FRESH');
+(new Date(props.asOf).toLocaleString());
+// @ts-ignore
+[stale, stale, stale,];
+const __VLS_export = (await import('vue')).defineComponent({
+    __typeProps: {},
+});
+export default {};