refactor: standardize notify helper usage and document migration workflow

- Refactor notify usage in GiftedDialog.vue, AccountViewView.vue, ClaimView.vue, and DataExportSection.vue:
  • Use notify as a property initialized in created() with createNotifyHelpers(this.$notify)
  • Remove getter-based notify patterns for consistency and lifecycle safety
  • Fix linter/type errors related to notify property initialization

- Add mandatory per-file migration workflow to doc/migration-progress-tracker.md:
  • For each file: (1) migrate to PlatformServiceMixin, (2) immediately standardize notify usage and fix linter/type errors
  • Clarifies this two-step process is required for every file, not as a global sweep

All migrated files are now consistent, maintainable, and ready for further migration work.

doc/migration-to-wa-sqlite.md

@@ -231,7 +231,7 @@ import { logger } from '../utils/logger';
 logger.debug('[Migration] Starting migration process...');
 const result = await migrateAll();
 logger.debug('[Migration] Migration completed:', result);
-```
+   ```
 
 ## Benefits of PlatformServiceMixin Approach