[BUG] Cowork project groups disappeared after update (desktop + web), v1.22209.3

Environment: macOS, Claude Desktop v1.22209.3

What happened: After a routine app update/restart, all Cowork project groups disappeared from the sidebar and from the Projects page — approximately 6-7 actively-used projects across 3 businesses (names redacted; available to Anthropic staff privately on request), all with connected folders and saved instructions. Same behavior in the web version, suggesting this is server-side (project index), not a local app issue.

What still works: Individual Cowork sessions remained intact at first and open normally from Recents. Project instructions still apply inside existing sessions. Underlying data (connected cloud-storage folders, GitHub repos, external task trackers) is untouched.

What's broken: The Projects page no longer lists the affected projects, so new sessions can't be created under them. Cross-session Cowork project memory also stopped working mid-session ("this session is not associated with a project on this device" error), even for a session that previously had working memory access.

This matches a recurring pattern in prior reports — the underlying project/session files reportedly stay intact on disk while the UI's project index fails to rebuild after an update: #49276, #56484 (both closed as duplicates, plus an older #35131).

Could someone confirm whether the project index can be rebuilt server-side, and whether there's a fix in progress given this appears to recur every few months?

(Edited: project/business names redacted for privacy. Full details shared with Anthropic privately via in-app feedback with diagnostic logs and task transcript.)