- Add helpers/company_context.py with get_active_company_id() fallback logic
- Add inject_company_context() context processor to app.py (user_companies, active_company, has_multiple_companies)
- Add /api/switch-company/<id> POST endpoint in public blueprint
- Set session['active_company_id'] on login (both standard and 2FA paths)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
