feat(auth): integrate NextAuth.js with Supabase authentication

[Paddy1981]

• Add Supabase client configuration (web/src/lib/supabase.ts)
• Add NextAuth.js configuration with multiple providers:
  • Google OAuth
  • GitHub OAuth
  • Email/Password credentials via Supabase
• Create NextAuth API route ([...nextauth]/route.ts)
• Add AuthProvider wrapper for session management
• Update login/register pages with OAuth buttons
• Add Supabase database migration schema:
  • users, accounts, sessions tables (NextAuth)
  • analyses, subscriptions, usage_records tables
  • Row-level security policies
  • Helper functions for usage limits
• Update environment template with Supabase variables

https://claude.ai/code/session_011NWj4qHMpnJqseDYB5et8R

Summary

Type of Change

• Bug fix (non-breaking change fixing an issue)
• New feature (non-breaking change adding functionality)
• Breaking change (fix or feature causing existing functionality to change)
• Documentation update
• Refactoring (no functional changes)
• CI/CD changes

Related Issues

Changes Made

Testing

• Unit tests added/updated
• Manual testing performed
• All existing tests pass

Skill Updates (if applicable)

• ANAL-xxx:
• STAR-xxx:
• MISSION-xxx:
• DISC-xxx:
• RES-xxx:

Multi-IDE Coordination

• Updated .coordination/TASK_LOG.md
• Checked .coordination/FILE_LOCKS.md for conflicts
• Updated .coordination/HANDOFF_NOTES.md if needed

Checklist

• Code follows project style guidelines
• Self-review completed
• Comments added for complex logic
• Documentation updated (if needed)
• No new warnings introduced