Unsharing or deleting a session leaves /api/share/:id/data publicly visible

Summary

After a session is unshared (via /unshare) or deleted, the conversation data is still publicly visible. The share page may show "Not Found", but the raw conversation remains readable at /api/share/:id/data with no authentication.

Steps to reproduce

1. Create a shared session.
2. Run /unshare (or DELETE /api/share/:id with the share secret).
3. The share page shows "Not Found", but GET /api/share/:id/data still returns the full conversation JSON.

Observed behavior

• The delete/unshare endpoint returns 500 Internal Server Error in this state.
• GET /api/share/:id/data continues to serve the entire conversation (hundreds of messages) to anyone with the link.
• The data endpoint is cached with stale-while-revalidate=86400, so the CDN can keep serving the content long after the unshare.

Expected behavior

Unsharing or deleting a session should fully remove both the share page and the backing /api/share/:id/data payload — including CDN invalidation — so the conversation is no longer publicly accessible.

Impact

Privacy issue: conversation content can remain publicly accessible after the user believes they have unshared or deleted it.

Request

1. Fix unshare/delete so it reliably removes both the page and the data (with CDN purge).
2. Provide a private channel (DM / email) where an affected share ID can be reported for urgent server-side purge, since the ID should not be posted publicly.

Thanks!