feat: implement debug logging cleanup and i18n coverage proposals

## cleanup-debug-logging
- Create environment-aware logger utility (logger.ts)
- Replace 60+ console.log/error statements across 28 files
- Production: only warn/error logs visible
- Development: all log levels with prefixes

Updated files:
- Contexts: NotificationContext, ProjectSyncContext, AuthContext
- Components: GanttChart, CalendarView, ErrorBoundary, and 11 others
- Pages: Tasks, Projects, Dashboard, and 7 others
- Services: api.ts

## complete-i18n-coverage
- WeeklyReportPreview: all strings translated, dynamic locale
- ReportHistory: all strings translated, dynamic locale
- AuditPage: detail modal and verification modal translated
- WorkloadPage: error message translated

Locale files updated:
- en/common.json, zh-TW/common.json: reports section
- en/audit.json, zh-TW/audit.json: modal sections
- en/workload.json, zh-TW/workload.json: errors section

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

openspec/changes/cleanup-debug-logging/tasks.md

@@ -1,28 +1,28 @@
 ## 1. Create Logging Utility
-- [ ] 1.1 Create `utils/logger.ts` with environment-aware logging
-- [ ] 1.2 Export debug, info, warn, error functions
-- [ ] 1.3 Only output logs when `import.meta.env.DEV` is true
+- [x] 1.1 Create `utils/logger.ts` with environment-aware logging
+- [x] 1.2 Export debug, info, warn, error functions
+- [x] 1.3 Only output logs when `import.meta.env.DEV` is true
 
 ## 2. Cleanup Context Files
-- [ ] 2.1 Remove/replace console statements in NotificationContext.tsx
-- [ ] 2.2 Remove/replace console statements in ProjectSyncContext.tsx
-- [ ] 2.3 Remove/replace console statements in AuthContext.tsx
+- [x] 2.1 Remove/replace console statements in NotificationContext.tsx
+- [x] 2.2 Remove/replace console statements in ProjectSyncContext.tsx
+- [x] 2.3 Remove/replace console statements in AuthContext.tsx
 
 ## 3. Cleanup Component Files
-- [ ] 3.1 Remove/replace console statements in GanttChart.tsx
-- [ ] 3.2 Remove/replace console statements in CalendarView.tsx
-- [ ] 3.3 Audit and clean remaining components
+- [x] 3.1 Remove/replace console statements in GanttChart.tsx
+- [x] 3.2 Remove/replace console statements in CalendarView.tsx
+- [x] 3.3 Audit and clean remaining components
 
 ## 4. Cleanup Page Files
-- [ ] 4.1 Remove/replace console statements in Tasks.tsx
-- [ ] 4.2 Remove/replace console statements in other page files
-- [ ] 4.3 Audit and clean remaining pages
+- [x] 4.1 Remove/replace console statements in Tasks.tsx
+- [x] 4.2 Remove/replace console statements in other page files
+- [x] 4.3 Audit and clean remaining pages
 
 ## 5. Cleanup Service Files
-- [ ] 5.1 Remove/replace console statements in api.ts
-- [ ] 5.2 Audit and clean remaining services
+- [x] 5.1 Remove/replace console statements in api.ts
+- [x] 5.2 Audit and clean remaining services
 
 ## 6. Verification
-- [ ] 6.1 Run frontend build successfully
-- [ ] 6.2 Verify no console.log in production build
-- [ ] 6.3 Test error handling still works correctly
+- [x] 6.1 Run frontend build successfully
+- [x] 6.2 Verify no console.log in production build
+- [x] 6.3 Test error handling still works correctly