Variable LoginServiceConst

Service for authenticating users via email-based passwordless login.

Authentication Flow:

1. Client calls Login with the user's email address
2. If the email is registered, a six-digit code is sent to that email
3. Client receives an auth_flow_token and EmailCode response
4. User enters the code from their email
5. Client calls EmailCode with the auth_flow_token and the code
6. If valid, client receives a JWT token; if invalid, receives a Failure

Security Features:

• Rate limited to 20 requests per 10 minutes per origin to prevent brute force attacks
• Auth flow tokens expire after 15 minutes
• Same response for registered and unregistered emails to prevent email enumeration
• Invalid codes return the same error as expired/invalid flow tokens to prevent timing attacks

Error Handling:

• RESOURCE_EXHAUSTED: Rate limit exceeded (too many login attempts)
• UNAUTHENTICATED: No origin header provided (required for rate limiting)
• INTERNAL: Unexpected server error during processing