feat: share chats

[leoisadev1]

1. be able to share chats
2. support dynamic open graph image generation for shared chats like grok

[tembo]

Good feature request. Here's some context from the codebase that could inform the implementation:

Current chat structure & access model:

• Chats are stored in the chats table in Convex (apps/server/convex/schema.ts) with a userId field for ownership
• All chat queries enforce strict ownership validation (see assertOwnsChat in apps/server/convex/chats.ts)
• Chat IDs are Convex UUIDs with a route pattern of /c/$chatId (apps/web/src/routes/c/$chatId.tsx)
• Currently there's no isPublic field on chats (that pattern exists only on promptTemplates)

Existing patterns you could leverage:

1. Export endpoint pattern (apps/web/src/routes/api/workflow/export-chat.ts):

   • Shows how to validate auth, rate limit, and transform chat data
   • Could be adapted for generating shared chat data

2. Fork feature (apps/server/convex/chatFork.ts, apps/web/src/hooks/use-fork-message.ts):

   • Already creates linkages between related chats (forkedFromChatId)
   • Shows how to track chat relationships

3. Meta handling for social preview:

   • Current chat page uses static meta tags ("noindex, nofollow", static title)
   • You'll likely need to make these dynamic for shared links (see apps/web/src/routes/c/$chatId.tsx)

Implementation considerations:

• For sharing: You'll probably want to add a shareToken or similar field to chats, separate from the chat ID, to enable sharing without exposing internal UUIDs
• For dynamic OG images: Consider generating these server-side (possibly via a Convex action) rather than at build time, since you have message history available
• Make sure to maintain the existing ownership checks - shared chats should still respect privacy (read-only access, no editing)
• The soft-delete pattern used elsewhere (see chatExport.ts) could help with managing share state

Looking at Grok's approach, they likely generate OG images with a preview of the conversation. This could involve rendering message content, maybe the first few exchanges, and branding.

Would this be public/unauthenticated sharing or just shareable links within your user network?