Account Security & GitHub OAuth

What’s New

• Added GitHub OAuth login (signup and link existing account)
• Added profile photo upload to Cloudflare R2
• Added POST /auth/change-password with token rotation
• Added DELETE /auth/account with password confirmation
• Added PATCH /auth/profile for name and email updates

Improvements

• Settings security page now uses real change-password flow
• Forced logout after password change with redirect state
• Limited external email delivery to production environment

Fixes

• Fixed login error triggering full page reload via axios interceptor
• Fixed TikTok downloader URL validation (trimming, shortlinks)
• Fixed SoundCloud DTO validation for on.soundcloud.com shortlinks