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/complete-i18n-coverage/tasks.md

@@ -1,30 +1,30 @@
 ## 1. WeeklyReportPreview i18n
-- [ ] 1.1 Add translation keys for report labels and status names
-- [ ] 1.2 Add translation keys for error and loading messages
-- [ ] 1.3 Replace hardcoded strings with t() calls
-- [ ] 1.4 Use dynamic locale for date formatting
+- [x] 1.1 Add translation keys for report labels and status names
+- [x] 1.2 Add translation keys for error and loading messages
+- [x] 1.3 Replace hardcoded strings with t() calls
+- [x] 1.4 Use dynamic locale for date formatting
 
 ## 2. ReportHistory i18n
-- [ ] 2.1 Add translation keys for history labels
-- [ ] 2.2 Add translation keys for loading/empty states
-- [ ] 2.3 Replace hardcoded strings with t() calls
+- [x] 2.1 Add translation keys for history labels
+- [x] 2.2 Add translation keys for loading/empty states
+- [x] 2.3 Replace hardcoded strings with t() calls
 
 ## 3. AuditPage Modal i18n
-- [ ] 3.1 Add translation keys for detail modal labels
-- [ ] 3.2 Add translation keys for verification modal
-- [ ] 3.3 Add translation keys for field names and status messages
-- [ ] 3.4 Replace hardcoded strings with t() calls
+- [x] 3.1 Add translation keys for detail modal labels
+- [x] 3.2 Add translation keys for verification modal
+- [x] 3.3 Add translation keys for field names and status messages
+- [x] 3.4 Replace hardcoded strings with t() calls
 
 ## 4. WorkloadPage i18n
-- [ ] 4.1 Replace hardcoded error message with t() call
+- [x] 4.1 Replace hardcoded error message with t() call
 
 ## 5. Update Locale Files
-- [ ] 5.1 Add all new keys to en/common.json
-- [ ] 5.2 Add all new keys to zh-TW/common.json
-- [ ] 5.3 Verify key structure consistency
+- [x] 5.1 Add all new keys to en/common.json
+- [x] 5.2 Add all new keys to zh-TW/common.json
+- [x] 5.3 Verify key structure consistency
 
 ## 6. Verification
-- [ ] 6.1 Test English locale displays correctly
-- [ ] 6.2 Test Chinese locale displays correctly
-- [ ] 6.3 Verify no untranslated strings remain
-- [ ] 6.4 Frontend builds successfully
+- [x] 6.1 Test English locale displays correctly
+- [x] 6.2 Test Chinese locale displays correctly
+- [x] 6.3 Verify no untranslated strings remain
+- [x] 6.4 Frontend builds successfully