feature/(auth): Handle users with invalid email addresses in OAuth ca…

[hongwei1]

…llback

• Remove email requirement from user validation check, only require user_id
• Add validation logic to detect placeholder email addresses (@noemail.local)
• Log warning when users login without valid email addresses
• Include commented code for optional redirect to profile page for email updates
• Update error message to reflect that only user_id is required for validation
• Allows users with placeholder emails to proceed with session creation while flagging for potential email update