Fix model naming conventions: remove user- prefix from rotation/autoselect model IDs, fetch live provider models

- Add user_id parameter to ContextManager
- Check database for user-specific prompts before filesystem
- Pass user_id from RequestHandler to ContextManager
- Update autoselect prompt loading to respect user-specific prompts
- All authenticated requests get user-specific prompts when available
- Global tokens skip database lookup entirely

- Make user_rotations.html and user_autoselects.html identical to admin templates
- Remove global config fallback for database users in handlers
- Separate provider/rotation visibility: users only see their own, admin only global
- Update version to 0.99.38

The /tmp directory often doesn't allow web servers to create subdirectories. Now uses:
- Config admin: ~/.aisbf/temp_uploads/
- Database users: ~/.aisbf/user_auth_files/{user_id}/temp_uploads/

This ensures uploads work in all environments including restrictive web server configurations.

5MB chunks were still hitting reverse proxy limits for some configurations. 1MB is universally supported and will work with nginx, Cloudflare, and all other reverse proxies with default configurations.