Switch handleSetHostCredentials, handleSetAdminCredentials, and
handleDeleteAdminCredentials from authedUser (bool) to requireUser
(*store.User) so AuditEntry.UserID and Actor are populated correctly.
Add slog.Warn on the non-ErrNotFound pushAdminCredsToAgent path in
handleRunRepoPrune so decrypt/send failures surface in the server log
rather than appearing as a generic host_offline 503.
Adds POST /api/hosts/{id}/repo/{prune,check,unlock} (and matching outer
routes for HTMX form posts). Prune pushes the admin-cred slot via
pushAdminCredsToAgent before dispatch and refuses with
admin_creds_required when the slot is not set. Check reads
check_subset_pct from host_repo_maintenance (overridable via ?subset=N,
clamped 0-100; non-numeric override falls back to DB value silently).
Unlock needs no admin creds. All three share the same wantsHTML/HX-Redirect
response split as the per-source-group run-now endpoint.
steve