feat(learn): add 3 new courses — Ramadan Fasting, Zakat, Hajj & Umrah

- 15 new modules with 2000-3000 char markdown content
- 1 quiz question per module with explanation
- audioPath set to .m4a for all 15 modules (TTS-ready)
- Added local TTS generation script (scripts/generate-tts-local.js)
- Added .gitignore for generated audio files
- Total: 7 courses, 32 modules in seed-learn.json

Note: Audio files are generated locally via generate-tts-local.js.
They are excluded from git (see .gitignore) due to large binary size.
For production MP3s, use Azure/ElevenLabs via Gitea's generate-audio.py.

.gitignore

@@ -40,3 +40,7 @@ yarn-error.log*
 *.tsbuildinfo
 next-env.d.ts
 .gstack/
+
+# generated TTS audio (large binary files — run scripts/generate-tts-local.js locally)
+public/audio/learn/**/*.m4a
+public/audio/learn/**/*.wav