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/admin/users.php

@@ -121,81 +121,4 @@
     </div>
 </div>
 
-<script>
-function showCreateUserModal() {
-    document.getElementById('modalTitle').textContent = 'Create User';
-    document.getElementById('userId').value = '';
-    document.getElementById('modalUsername').value = '';
-    document.getElementById('modalEmail').value = '';
-    document.getElementById('modalPassword').value = '';
-    document.getElementById('modalPassword').required = true;
-    document.getElementById('passwordHint').style.display = 'block';
-    document.getElementById('modalRole').value = 'admin';
-    document.getElementById('modalActive').checked = true;
-    document.getElementById('saveUserBtn').textContent = 'Create';
-    document.getElementById('userModal').style.display = 'flex';
-}
-
-function editUser(id, username, email, role, isActive) {
-    document.getElementById('modalTitle').textContent = 'Edit User';
-    document.getElementById('userId').value = id;
-    document.getElementById('modalUsername').value = username;
-    document.getElementById('modalEmail').value = email;
-    document.getElementById('modalPassword').value = '';
-    document.getElementById('modalPassword').required = false;
-    document.getElementById('passwordHint').style.display = 'none';
-    document.getElementById('modalRole').value = role;
-    document.getElementById('modalActive').checked = !!isActive;
-    document.getElementById('saveUserBtn').textContent = 'Update';
-    document.getElementById('userModal').style.display = 'flex';
-}
-
-function closeModal() {
-    document.getElementById('userModal').style.display = 'none';
-}
-
-function saveUser() {
-    const id = document.getElementById('userId').value;
-    const formData = new FormData(document.getElementById('userForm'));
-
-    const isEdit = !!id;
-    const url = isEdit ? '/admin/users/' + id + '/update' : '/admin/users/create';
-
-    fetch(url, {
-        method: 'POST',
-        headers: {
-            'X-CSRF-Token': document.querySelector('meta[name="csrf-token"]')?.content || '',
-        },
-        body: new URLSearchParams(formData),
-    })
-    .then(r => r.json())
-    .then(data => {
-        if (data.success) {
-            showToast('success', data.message);
-            setTimeout(() => location.reload(), 1000);
-        } else {
-            showToast('error', data.message);
-        }
-        closeModal();
-    })
-    .catch(err => showToast('error', 'Failed to save user'));
-}
-
-function deleteUser(id, username) {
-    if (!confirm('Are you sure you want to delete user "' + username + '"?')) return;
-
-    fetch('/admin/users/' + id + '/delete', {
-        method: 'POST',
-        headers: {
-            'Content-Type': 'application/x-www-form-urlencoded',
-            'X-CSRF-Token': document.querySelector('meta[name="csrf-token"]')?.content || '',
-        },
-        body: '_csrf_token=' + encodeURIComponent(document.querySelector('meta[name="csrf-token"]')?.content || ''),
-    })
-    .then(r => r.json())
-    .then(data => {
-        if (data.success) location.reload();
-        else showToast('error', data.message);
-    });
-}
-</script>
+<script src="/assets/js/admin-users.js"></script>