cms mode: primo dev --author cms deletes site content files from disk (recovered twice from .primo/trash) #1241

What happened

While running primo dev --author cms against a local workspace, site content was deleted from disk twice in one session. Deleted from both test sites in the workspace:

• pages/
• page-types/
• site/
• most of blocks/

Files were moved to .primo/trash/ with names of the form <ISO8601>_<Site Name>_<path with __ separators>, which is the only reason they were recoverable. The workspace is not a git repo. Recovery: copy the newest trash entry per unique path back into place, skipping destinations that already exist.

Possible causes to investigate

• CMS→file sync treating "absent in CMS" as "delete from disk" (i.e. the CMS DB was missing the content, and sync propagated that as deletions rather than as a desync to flag)
• Deletion may be intended in cms mode, in which case the real bug is the absence of any warning/confirmation before destructive sync
• Possibly triggered by mode-switching during the session (files → cms → files)
• Possible precondition rather than coincidence: an empty sites/coffee-shop/page-types/default/head.svelte was hand-created and then deleted shortly before the first loss

Open questions

• Is deletion of disk files reachable in a normal cms-mode workflow, or only via mode-switching?
• Is there any warning path at all today?
• Does the trash naming carry enough information to script recovery reliably?

Reproduction notes

⚠️ The affected workspace was reproducibly destroyed by this command — do not run it against a workspace you care about. Any investigation should use a copy of the workspace.

Discovered during verification of #1233 (browse mode).