Limit recursive poll file watching

[karimknaebel]

Draft PR to highlight a file watcher issue seen on NFS-backed paths.

Zed switches these paths to the polling watcher. The poll watcher can then recurse from the worktree root and repeatedly walk large generated or ignored directories. In my case this kept the Zed server process busy and completely prevented the file tree and search from populating.

The important issue is that recursive polling appears too broad for this filesystem case.

[karimknaebel]

Possibly related:
#54481
#38109

[karimknaebel]

@probably-neb i think this might be related to recent fs watch changes from your side. let me know if i can help you in any way to reproduce this problem :)

[karimknaebel]

@kubkon tagging you here since you reviewed #54481

the main issue seems to be that recursively watching a large dir with the poll watcher (especially on NFS) completely overwhelms the remote server process to the point where the file tree doesn't populate, search doesn't work, etc.

[ChristopherBiscardi]

closing since this never made it out of draft status, and the referenced issues/prs in comments have been merged/closed