feat: restrict backup archive download to primary admin and hide admin-hidden projects from other admins

- Add `get_admin_uids()` and `get_primary_admin_uid()` to database.py for resolving the earliest-created admin
- Modify `can_view_project()` in content.py so a project hidden by an admin is invisible to other admins (both web UI and REST API)
- Update `_download_url()` and `_backup_payload()` in admin/backups.py to accept a `can_download` flag, gating the download endpoint with `is_primary_admin()`
- Remove `role` from `_user_facts()` in docs_live.py to avoid leaking admin status in live docs
- Update doc summaries in docs_api.py to reflect the new admin-visibility and backup-download semantics

devplacepy/static/css/base.css

@@ -585,7 +585,7 @@ img {
 .topnav-user:hover { background: var(--bg-card); }
 .topnav-user-info { display: flex; flex-direction: column; line-height: 1.2; }
 .topnav-user-name { font-size: 0.8125rem; font-weight: 600; color: var(--text-primary); }
-.topnav-user-role { font-size: 0.6875rem; color: var(--text-muted); }
+.topnav-user-level { font-size: 0.6875rem; color: var(--text-muted); }
 .topnav-user-dropdown { position: relative; }
 .topnav-user-dropdown .dropdown-menu {
     display: none;
@@ -724,7 +724,7 @@ img {
     line-height: 1.2;
 }
 
-.topnav-mobile-user-role {
+.topnav-mobile-user-level {
     font-size: 0.75rem;
     color: var(--text-muted);
     font-weight: 400;

devplacepy/static/css/feed.css

@@ -96,7 +96,7 @@
     color: var(--text-primary);
 }
 
-.post-author-role {
+.post-author-level {
     font-size: 0.6875rem;
     color: var(--text-muted);
     font-weight: 400;

devplacepy/static/css/post.css

@@ -25,7 +25,7 @@
     font-size: 0.9375rem;
 }
 
-.post-detail-role {
+.post-detail-level {
     font-size: 0.75rem;
     color: var(--text-muted);
     font-weight: 400;

devplacepy/static/css/profile.css

@@ -36,13 +36,6 @@
     word-break: break-word;
 }
 
-.profile-role {
-    font-size: 0.8125rem;
-    color: var(--text-muted);
-    font-weight: 500;
-    margin-bottom: 1rem;
-}
-
 .profile-stats {
     display: flex;
     justify-content: center;