refactor: extract inline CSS/JS from views into separate asset files (20+ files)

Phase A — HTML removed from PHP files:
- RateLimitMiddleware.php: heredoc moved to views/errors/429.php
- public/index.php: inline HTML replaced with View::error()
- AuthMiddleware.php: <script> redirect replaced with <meta refresh>

Phase B — Inline CSS/JS extracted from views:
- CSS: landing.css (459 lines), legal.css (shared by terms+privacy)
- JS: 17 new files extracted from ~20 view files
  - main.js (layout sidebar + notifications)
  - dashboard-chart.js, server-show.js, server-services.js
  - nginx-manager.js, database-manager.js
  - terminal.js, team-show.js, team-index.js
  - server-list.js, server-permissions.js (shared by edit+create)
  - server-ssl.js, server-processes.js, system-users.js
  - admin-users.js, audit-log.js, admin-notifications.js, admin-security.js
  - notifications.js

Total: -3264 lines from views, +288 lines in new assets

views/servers/system_users.php

@@ -121,46 +121,6 @@ $lastLogins = $sysusers['last_logins'] ?? '';
 </div>
 
 <script>
-function getCsrfToken() { return document.querySelector('meta[name="csrf-token"]')?.content || ''; }
-
-function showAddUser() { document.getElementById('addUserModal').style.display = 'flex'; }
-function showAddGroup() { document.getElementById('addGroupModal').style.display = 'flex'; }
-function closeModal(id) { document.getElementById(id).style.display = 'none'; }
-
-function doAddUser() {
-    const data = 'action=add&username=' + encodeURIComponent(document.getElementById('suUser').value)
-        + '&password=' + encodeURIComponent(document.getElementById('suPass').value)
-        + '&groups=' + encodeURIComponent(document.getElementById('suGroups').value)
-        + '&create_home=' + (document.getElementById('suHome').checked ? '1' : '0')
-        + '&_csrf_token=' + encodeURIComponent(getCsrfToken());
-    fetch('/servers/<?= $server['id'] ?>/users', {method:'POST', headers:{'Content-Type':'application/x-www-form-urlencoded','X-CSRF-Token':getCsrfToken()}, body:data})
-    .then(r=>r.json()).then(d=>{showToast(d.success?'success':'error',d.message);if(d.success)setTimeout(()=>location.reload(),800)});
-    closeModal('addUserModal');
-}
-
-function doAddGroup() {
-    const data = 'action=addgroup&group=' + encodeURIComponent(document.getElementById('sgGroup').value) + '&_csrf_token=' + encodeURIComponent(getCsrfToken());
-    fetch('/servers/<?= $server['id'] ?>/users', {method:'POST', headers:{'Content-Type':'application/x-www-form-urlencoded','X-CSRF-Token':getCsrfToken()}, body:data})
-    .then(r=>r.json()).then(d=>{showToast(d.success?'success':'error',d.message);if(d.success)setTimeout(()=>location.reload(),800)});
-    closeModal('addGroupModal');
-}
-
-function lockUser(u) {
-    if(!confirm('Lock user \''+u+'\'?'))return;
-    fetch('/servers/<?= $server['id'] ?>/users', {method:'POST', headers:{'Content-Type':'application/x-www-form-urlencoded','X-CSRF-Token':getCsrfToken()}, body:'action=lock&username='+encodeURIComponent(u)+'&_csrf_token='+encodeURIComponent(getCsrfToken())})
-    .then(r=>r.json()).then(d=>{showToast(d.success?'success':'error',d.message);if(d.success)setTimeout(()=>location.reload(),800)});
-}
-
-function unlockUser(u) {
-    fetch('/servers/<?= $server['id'] ?>/users', {method:'POST', headers:{'Content-Type':'application/x-www-form-urlencoded','X-CSRF-Token':getCsrfToken()}, body:'action=unlock&username='+encodeURIComponent(u)+'&_csrf_token='+encodeURIComponent(getCsrfToken())})
-    .then(r=>r.json()).then(d=>{showToast(d.success?'success':'error',d.message);if(d.success)setTimeout(()=>location.reload(),800)});
-}
-
-function deleteUser(u) {
-    if(!confirm('Delete user \''+u+'\'?\nThis cannot be undone.'))return;
-    fetch('/servers/<?= $server['id'] ?>/users', {method:'POST', headers:{'Content-Type':'application/x-www-form-urlencoded','X-CSRF-Token':getCsrfToken()}, body:'action=delete&username='+encodeURIComponent(u)+'&_csrf_token='+encodeURIComponent(getCsrfToken())})
-    .then(r=>r.json()).then(d=>{showToast(d.success?'success':'error',d.message);if(d.success)setTimeout(()=>location.reload(),800)});
-}
-
-document.addEventListener('keydown',function(e){if(e.key==='Escape'){closeModal('addUserModal');closeModal('addGroupModal')}});
+const serverId = <?= $server['id'] ?>;
 </script>
+<script src="/assets/js/system-users.js"></script>