Description

Implements account deletion functionality as requested in #603. This adds a comprehensive soft-delete system that allows users to permanently delete their accounts while preserving system integrity.

Closes #603

Key Features:

• Soft delete with deletedAt timestamp to maintain referential integrity
• User data anonymization (nullifies email, pubkey, auth tokens, etc.)
• All user content is transferred to the special @delete user account
• Content titles and bodies are replaced with "deleted by author" (using existing deletion logic)
• Balance handling - users must withdraw or donate remaining sats/credits to rewards pool
• Proper authentication checks to reject deleted accounts
• UI integration in settings with confirmation flow
• Username hashing to prevent unique constraint issues

Technical Implementation:

• Added deletedAt field to User model with database migration
• Created deleteAccount GraphQL mutation with proper validation
• Modified authentication flow to check for deleted accounts in NextAuth callbacks
• Updated zap distribution to handle deleted users (credits go to rewards pool)
• Content from deleted users cannot be zapped (throws error)
• Comprehensive transaction handling to ensure data consistency

Content Handling:

• All user items are transferred to the special @delete user (USER_ID.delete = 106)
• Content is processed through existing deleteItemByAuthor function
• Titles and bodies are replaced with "deleted by author" text
• No content hashing - uses standard deletion approach
• Deleted content cannot be zapped or voted on

Authentication & Session Management:

• NextAuth JWT callback checks for deleted accounts and prevents sign-in
• Session callback validates user status on each request
• Automatic logout after successful account deletion
• SSR Apollo client handles deleted user states

Balance & Rewards:

• Users must either withdraw balance or confirm donation to rewards pool
• Donated balance is converted from msats to sats and added to donations table
• Future zaps to deleted user content automatically go to rewards pool
• Earnings from deleted users in zap distribution are donated to rewards pool

Screenshots

Additional Context

Key implementation decisions:

1. Content Strategy: All content is transferred to @delete user and processed through existing deletion logic rather than being hashed or anonymized
2. Balance Handling: Added option to donate remaining balance to rewards pool rather than requiring complete withdrawal
3. Username Strategy: Hash username with deletion timestamp to prevent conflicts while maintaining anonymity
4. Zap Protection: Content from deleted users cannot be zapped (throws error in zap.js)
5. Rewards Distribution: Modified zap distribution to donate earnings that would go to deleted users to rewards pool

The authentication flow required updates in multiple places (NextAuth callbacks, SSR Apollo client, etc.) to properly handle deleted accounts across the application.

Checklist

Are your changes backwards compatible? Please answer below:
Yes, fully backwards compatible. Existing users are unaffected, and the deletedAt field is nullable. No breaking changes to existing APIs or database schema.

On a scale of 1-10 how well and how have you QA'd this change and any features it might affect? Please answer below:
7/10 - Tested core deletion flow, authentication rejection, UI display, and balance handling. Would benefit from additional testing of edge cases around zap distribution to @delete user.

For frontend changes: Tested on mobile, light and dark mode? Please answer below:
Yes - The settings UI changes were tested on mobile and dark mode.

Did you introduce any new environment variables? If so, call them out explicitly here:
No new environment variables introduced. Uses existing USER_ID.delete constant for the special delete user account.