Add admin features, user profile management, and generation capabilities

- Implemented admin dashboard with user management features including role assignment and deletion.
- Added user profile page for updating email and password.
- Created separate routes and templates for text, image, and video generation with appropriate forms.
- Enhanced navigation with dropdown for generation options and loading overlay for better user experience.
- Introduced comprehensive error handling and user feedback through alerts.
- Updated styles for improved UI consistency and responsiveness.

Co-authored-by: Copilot <copilot@github.com>

frontend/app/templates/admin.html

@@ -0,0 +1,68 @@
+{% extends "base.html" %}
+{% block title %}Admin — AI Allucanget{% endblock %}
+{% block content %}
+<div class="card">
+  <h1>Admin Dashboard</h1>
+
+  {% if stats %}
+  <div class="stats-grid">
+    <div class="stat-box">
+      <div class="stat-label">Total users</div>
+      <div class="stat-value">{{ stats.get('total_users', 0) }}</div>
+    </div>
+    <div class="stat-box">
+      <div class="stat-label">Active tokens</div>
+      <div class="stat-value">{{ stats.get('active_refresh_tokens', 0) }}</div>
+    </div>
+    <div class="stat-box">
+      <div class="stat-label">Admins</div>
+      <div class="stat-value">{{ stats.get('admin_users', 0) }}</div>
+    </div>
+  </div>
+  {% endif %}
+
+  <h2 class="section-title">Users</h2>
+  <div class="table-wrap">
+    <table>
+      <thead>
+        <tr>
+          <th>Email</th>
+          <th>Role</th>
+          <th>Actions</th>
+        </tr>
+      </thead>
+      <tbody>
+        {% for u in users %}
+        <tr>
+          <td>{{ u.email }}</td>
+          <td>
+            <span class="role-badge role-{{ u.role }}">{{ u.role }}</span>
+          </td>
+          <td>
+            <div class="table-actions">
+              <!-- Role toggle -->
+              <form method="post" action="{{ url_for('admin_set_role', user_id=u.id) }}">
+                <input type="hidden" name="role"
+                       value="{{ 'user' if u.role == 'admin' else 'admin' }}">
+                <button type="submit" class="btn btn-sm">
+                  Make {{ 'user' if u.role == 'admin' else 'admin' }}
+                </button>
+              </form>
+              <!-- Delete -->
+              {% if u.id != session.get('user_id') %}
+              <form method="post" action="{{ url_for('admin_delete_user', user_id=u.id) }}"
+                    onsubmit="return confirm('Delete {{ u.email }}?')">
+                <button type="submit" class="btn btn-sm btn-danger">Delete</button>
+              </form>
+              {% endif %}
+            </div>
+          </td>
+        </tr>
+        {% else %}
+        <tr><td colspan="3" class="text-muted">No users found.</td></tr>
+        {% endfor %}
+      </tbody>
+    </table>
+  </div>
+</div>
+{% endblock %}