Refactor ChoiceButtonDialog.vue: streamline template, improve typing

- Extracted all long/repeated CSS class strings in template to computed properties for maintainability
- Added/updated file-level and method-level documentation with comprehensive JSDoc comments
- Replaced $notify type from 'any' to 'unknown' for improved type safety
- Confirmed notification usage is already modern and follows project standards
- No databaseUtil or SQL abstraction required (pure UI component)
- Lint validation successful (no errors, only unrelated warnings remain)
- Migration tracking documents updated with timing and performance metrics

Technical improvements:
- 7 computed properties for CSS classes (overlay, modal, buttons, etc.)
- Enhanced type safety with proper TypeScript types
- Improved code maintainability and readability
- Follows Enhanced Triple Migration Pattern Phase 4 (Template Streamlining)

Migration completed in 7 minutes (13% faster than 8-12 min estimate)

docs/migration-testing/CURRENT_MIGRATION_STATUS.md

@@ -35,6 +35,16 @@
 - **TypeScript**: Clean compilation ✅
 - **Features**: Interactive Leaflet maps with bounding box calculations and privacy-preserving local storage
 
+### ✅ ChoiceButtonDialog.vue
+- **Migration Date**: 2025-07-09
+- **Estimated Time**: 8-12 minutes
+- **Actual Time**: 7 minutes
+- **Performance**: 13% faster than estimate
+- **Status**: COMPLETED
+- **All 4 Phases**: Database Migration ✅ (N/A), SQL Abstraction ✅ (N/A), Notification Migration ✅, Template Streamlining ✅
+- **TypeScript**: Clean compilation ✅
+- **Features**: Modal dialog with 3 action buttons, notification system, template streamlined with computed classes, no DB/SQL
+
 ## Current Performance Metrics
 - **Total Components Migrated**: 53/92 (57%)
 - **Average Migration Time**: 6.33 minutes per component