Summary

Adds a personal invite link system for challenges that allows users to share unique codes with friends. When someone joins via an invite link, the system automatically records who invited them and creates mutual follow relationships.

Key Changes

Backend:

• New challengeInvites table to store personal invite codes per user per challenge
• getOrCreateInviteCode mutation generates an 8-character alphanumeric code (idempotent)
• resolveInviteCode query resolves invite codes to challenge and inviter info
• Updated join mutation to accept inviteCode, resolve the inviter, and auto-create mutual follows
• New getMyInviteCode query to fetch existing codes

Frontend:

• New invite accept page at /challenges/[id]/invite/[code] that shows challenge details and join button
• Handles payment flow if challenge requires payment (stores invite code in sessionStorage for post-payment join)
• Handles auth redirects for unauthenticated users
• New InviteCard component pinned above activity feed until challenge starts
• Copy-to-clipboard and Web Share API integration for sharing links

Features

• Personal invite codes: Each user gets a unique code per challenge they join
• Auto-follow: Users who join via invite automatically follow each other (mutual)
• Payment support: Invite flow integrates with existing payment checkout
• Smart visibility: Invite card only shows before challenge starts
• Share options: Native share API with clipboard fallback

Testing

• pnpm lint
• pnpm typecheck
• Test invite code generation and idempotency
• Test joining via invite link (authenticated and unauthenticated)
• Test payment flow with invite codes
• Test mutual follow creation
• Test invite card visibility (shows before start, hides after)
• Test copy/share functionality

Notes

• Invite codes are 8 characters from a 55-character alphabet (no confusing chars like 0/O, 1/l, I)
• The invite accept page is public (no auth required) to allow unauthenticated users to see what they're joining
• Unauthenticated users are redirected to sign-up with a redirect URL back to the invite page
• Invite codes are stored in sessionStorage during payment flow to complete the join after checkout

https://claude.ai/code/session_01KiAJKNHGNMPzfLtKwVCMQ6