chore: v2.8.5 — Trash opens on one folder per user, server setup installs S3

- Files → Trash: ONE sidebar entry. An admin's opens on a folder per user's
  Trash (My Trash first, item counts from GET /api/homes/trash, an unreadable
  one showing its error); a folder opens that user's Trash (path bar
  Trash › user, Up back to the folders). An admin may restore/purge in
  another user's Trash (audited); purging asks first. The merged "All users"
  list is gone from the UI.
- A home's Trash is its user's whole recycle bin (home store + host store,
  items tagged `store`).
- `agenthub server setup` installs one Linux user per account on Linux by
  default (`--no-system` opts out); install-system messages drop `sudo`.
- Settings → Git: the author email suggests <username>@<AGENTHUB_EMAIL_DOMAIN>.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/plans/server-mode/S3-PLAN.md

@@ -112,7 +112,7 @@ Branch: `server-s3`. Commits happen only when the user asks.
 - Verify: an e2e against a fake upstream (header swapped, streaming kept, a dead pane's token refused, another member's profile refused).
 
 ### P2. Host setup (sudo; on this machine with the agh-test users)
-- [x] `sudo agenthub server install-system` is idempotent, has `--uninstall`, and does the following:
+- [x] `agenthub server install-system` is idempotent, has `--uninstall`, and does the following:
   - creates groups `agenthub` and `agenthub-members`;
   - creates `/srv/agenthub/users` (0751) and `/opt/agenthub/{tools,app,libexec,sbin}`;
   - writes the sudoers file and checks it with `visudo -c`;