Project cleanup deletes never-saved drafts by creation date, so a draft being edited right now can be removed #2677

What happens

findUnsavedProjectsOlderThan (src/db/queries/projects.ts:770) selects never-saved drafts by created_at:

.where('saved_once', '=', 0)
.where('created_at', '<', cutoffTime)

So the retention window runs from the moment the draft was created, not from the last time it was touched. A draft that is being edited right now is deleted as soon as it is old enough, together with its assets, its yjs_updates and its version history. Nothing excludes a project with a live WebSocket room.

With the default 24 h: a teacher starts a project on Monday morning, works on it all day without ever pressing Save, and on Tuesday morning the sweep deletes it mid-session.

The sibling query for guest projects, findGuestProjectsOlderThan (:811), already uses updated_at — so the two halves of the same cleanup disagree about what "older than" means.

Why it matters now

The behaviour is pre-existing, but two recent changes raise its reach:

• Cleanup scheduler: unset CLEANUP_* variables override the defaults with undefined #2670 meant partially-configured installations never actually deleted anything, so the path was rarely exercised.
• feat(admin): configure the project cleanup from /admin (#2671) #2673 puts the switch in /admin, where an administrator with no server access can turn it on, and Admin: allow enabling and configuring the project cleanup from /admin #2671 is a real installation with 196 of 203 projects in this state.

#2673 only corrects the wording — the help text now says drafts are deleted so many hours after they were created, even if they are still being edited — because changing which column is filtered is a behaviour change for an existing feature and deserves its own decision.

Options

1. Filter on updated_at, matching the guest query. Simple, strictly less destructive, and matches what most people read into "delete abandoned drafts". Projects that are genuinely abandoned still go; the ones being worked on do not.
2. Keep created_at and exclude projects with an open editing session (a live Yjs room, or a recent yjs_updates row). More faithful to "a draft should not live forever", more moving parts.
3. Keep it as it is and rely on the corrected wording.

My preference is 1: it removes a data-loss edge with one word, and it makes the two finders consistent. If a hard ceiling on draft lifetime is wanted, that is better expressed as a separate, much longer limit than as a side effect of this one.

Done when

• The chosen semantics are implemented in findUnsavedProjectsOlderThan, with a unit test in src/db/queries/projects.spec.ts covering a draft whose created_at is past the cutoff but whose updated_at is recent.
• The cleanup_unsaved_desc help string in src/routes/admin.ts matches whatever is implemented.