Hide backups of earlier guests that reused the VMID

Proxmox ties backups to the VMID only, so a deleted guest's backups
were listed under the new guest with that VMID. CT 104 showed planka
backups next to debian's, and VM 108 showed vaultwarden backups.

Backups whose notes name another guest are now hidden by default. The
notes come from the job's {{guestname}}, so "debian (manual)" still
counts as debian. A line says how many are hidden, and the a key shows
them, marked "(earlier guest)". Backups without notes are always
shown.

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

docs/plans/guest-tui-mvp.md

@@ -325,6 +325,11 @@ Observed CLI behaviour (cv4pve-cli 2.4.0, all read-only probes):
     Firewall (`yes`/`no`).
   - `DataTable#addresses`: Interface, MAC, IPv4, IPv6 (runtime), or the unavailable
     line.
+- VMIDs are reused: a deleted guest's backups keep the VMID and are listed by the API
+  for the new guest. Backups whose notes (the job's `{{guestname}}`) are non-empty and
+  are neither the current name nor start with `<name> ` (e.g. `debian (manual)`) are
+  hidden by default; `Static#hidden` says how many; key `a` toggles showing them,
+  marked `(earlier guest)`. Backups without notes are always shown.
 - Key `b` in InfoScreen: `BackupScreen` modal with `Select#storage` (options =
   backup storages, preselected `job_storage` or the first), text saying mode snapshot,
   zstd, and the guest; buttons `#yes` / `#no`; escape = no. On yes: guest marked busy