Fix PWA push notifications and add Icelandic WOD support

[Peleke]

Summary

• Fixes critical bugs preventing push notifications from working
• Adds Icelandic language support for Word of Day feature
• Creates test notification endpoint for debugging

Closes #134

Root Causes Fixed

1. Subscription Data Structure Mismatch (CRITICAL)

Subscribe endpoint saved nested JSONB { subscription: { endpoint, keys: { p256dh, auth } } } but CRON jobs expected flat structure { endpoint, p256dh_key, auth_key }.

2. Supabase Client Scope Issue

Helper functions in CRON jobs referenced supabase variable declared in outer GET handler scope.

3. Missing Push Event Handlers

Service worker auto-generated by Workbox lacked push and notificationclick event handlers.

4. Missing Test Endpoint

NotificationSettings UI called non-existent /api/admin/test-push-notification.

Changes Made

File	Change
app/api/cron/daily-notifications/route.ts	Fixed subscription parsing
app/api/cron/welcome-notifications/route.ts	Fixed parsing + Supabase scope
app/api/cron/daily-word-generation/route.ts	Fixed parsing + Supabase scope + Icelandic
app/api/admin/test-push-notification/route.ts	NEW - Test endpoint
worker/index.js	NEW - Custom SW with push handlers
next.config.ts	Added customWorkerDir: 'worker'
lib/mastra/tools/wordOfDay.ts	Added Icelandic word list
app/api/generate-word-of-day/route.ts	Added Icelandic validation
app/api/word-of-day/route.ts	Added Icelandic validation
app/api/word-of-day/fresh-sentences/route.ts	Added Icelandic validation
lib/mastra/workflows/wordOfDayGeneration.ts	Added Icelandic prompts

Test Plan

UAT: Push Notifications

TC1: Android Chrome

1. Open app in Chrome on Android
2. Go to Profile → Notification Settings
3. Click "Enable Notifications"
4. Accept browser permission prompt
5. Expected: Status shows "Notifications enabled"
6. Click "Test Notification"
7. Expected: Push notification received on device

TC2: iOS Safari PWA

1. Open app in Safari on iOS 16.4+
2. Tap Share → "Add to Home Screen"
3. Open app from Home Screen (required for iOS push)
4. Go to Profile → Notification Settings
5. Click "Enable Notifications"
6. Accept iOS permission prompt
7. Expected: Status shows "Notifications enabled"
8. Click "Test Notification"
9. Expected: Push notification received

TC3: Desktop Browser

1. Open app in Chrome/Firefox/Safari
2. Go to Profile → Notification Settings
3. Enable notifications and test
4. Expected: Desktop notification appears

UAT: Icelandic WOD

TC4: Generate Icelandic Word

curl -X POST https://staging.example.com/api/generate-word-of-day \
  -H "Content-Type: application/json" \
  -d '{"language": "icelandic", "date": "2024-01-15"}'

Expected: Returns Icelandic word with definitions

TC5: Fetch Icelandic Word

curl "https://staging.example.com/api/word-of-day?language=icelandic"

Expected: Returns word data for Icelandic

Verification Checklist

• Push notifications work on Android Chrome
• Push notifications work on iOS Safari (PWA installed)
• Push notifications work on desktop browsers
• Test notification button works
• Icelandic WOD generation works
• Existing Spanish/Latin WOD still works
• CRON job sends notifications correctly

🤖 Generated with Claude Code

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

[Peleke]

✅ UAT Complete

Tests Performed

PWA Installation

• Installed PWA on iOS Safari ✅
• App icon and splash screen display correctly ✅
• Standalone mode works ✅

Push Notifications (Partial)

• Notification permission prompt works ✅
• Service worker registration successful ✅
• Note: Full push notification testing requires mobile device + production VAPID keys

Word of Day - Icelandic Support

• Toggled language to Icelandic on WOD page ✅
• Icelandic words display with correct formatting ✅
• Audio pronunciation works via ElevenLabs ✅
• Dark mode styling applied correctly ✅

Supabase Scope Fix

• WOD fetches work without authentication errors ✅
• User preferences persist correctly ✅

Fixes Cherry-Picked from UAT

• ffc5e99 Fix WOD supabase scope bug and add dark mode support
• c3263c3 feat(wod): Add Icelandic language toggle to Word of Day page
• e160ca0 migration: Add Icelandic to daily_words language constraint

Migrations Required

1. 20260107_add_icelandic_to_daily_words.sql

Notes

• Supabase email templates for password reset need dashboard config check
• Full push notification testing recommended on mobile before production

Ready to merge 🚀