fix: 15 bug fixes for v3.1.0 dashboard and Track E features

Bug fixes (ordered by priority):
- BUG-14 (P1): Fix ImportError in per-user MCP endpoint
- BUG-8 (P2): Raise clear error when PUBLIC_URL missing for OAuth
- BUG-12 (P3): Validate ENCRYPTION_KEY at startup
- BUG-13 (P4): Handle stale JWT gracefully on site creation
- BUG-11 (P5): Add auth validation to WordPress health checks
- BUG-15 (P6): Fix copy button showing Python repr (dict method shadow)
- BUG-1 (P7): Dynamic version from pyproject.toml instead of hardcoded
- BUG-5 (P8): Fix server mode default (sse → streamable-http)
- BUG-9 (P9): Plugin-specific example tools in endpoint instructions
- BUG-4 (P10): Fix settings page sidebar RBAC (session type mismatch)
- BUG-6 (P11): Show real plugin descriptions instead of 'No description'
- BUG-2 (P12): Remove stale 'phase: X.3' from system info
- BUG-10 (P13): Guard timestamps against None in Recent Activity
- BUG-3 (P14): Guard timestamps against None in audit logs
- BUG-7 (P15): Styled 404 page instead of plain text

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/templates/dashboard/connect.html

@@ -22,7 +22,7 @@
             <p class="font-medium mb-1">{{ t.your_api_key }}</p>
             <div class="flex items-center gap-2">
                 <code class="bg-gray-100 dark:bg-gray-900 px-3 py-1 rounded text-sm flex-1 overflow-x-auto text-gray-800 dark:text-gray-200">{{ new_key }}</code>
-                <button onclick="copyText('{{ new_key }}')" class="text-sm text-yellow-700 dark:text-yellow-300 hover:text-yellow-600 dark:hover:text-yellow-200">{{ t.copy }}</button>
+                <button onclick="copyText('{{ new_key }}')" class="text-sm text-yellow-700 dark:text-yellow-300 hover:text-yellow-600 dark:hover:text-yellow-200">{{ t['copy'] }}</button>
             </div>
             <p class="text-xs text-yellow-600 dark:text-yellow-400 mt-1">{{ t.key_shown_once }}</p>
         </div>
@@ -33,7 +33,7 @@
             <p class="font-medium mb-1">{{ t.your_api_key }}</p>
             <div class="flex items-center gap-2">
                 <code id="new-key-value" class="bg-gray-100 dark:bg-gray-900 px-3 py-1 rounded text-sm flex-1 overflow-x-auto text-gray-800 dark:text-gray-200"></code>
-                <button onclick="copyNewKey()" class="text-sm text-yellow-700 dark:text-yellow-300 hover:text-yellow-600 dark:hover:text-yellow-200">{{ t.copy }}</button>
+                <button onclick="copyNewKey()" class="text-sm text-yellow-700 dark:text-yellow-300 hover:text-yellow-600 dark:hover:text-yellow-200">{{ t['copy'] }}</button>
             </div>
             <p class="text-xs text-yellow-600 dark:text-yellow-400 mt-1">{{ t.key_shown_once }}</p>
         </div>
@@ -104,7 +104,7 @@
 
         <div class="relative">
             <pre id="config-output" class="bg-gray-100 dark:bg-gray-900 rounded-lg p-4 text-sm text-gray-700 dark:text-gray-300 overflow-x-auto border border-gray-200 dark:border-gray-700 min-h-[120px]">Select a site and client to generate configuration...</pre>
-            <button onclick="copyConfig()" class="absolute top-2 {{ 'left-2' if lang == 'fa' else 'right-2' }} text-xs bg-gray-200 dark:bg-gray-700 hover:bg-gray-300 dark:hover:bg-gray-600 text-gray-600 dark:text-gray-300 px-3 py-1 rounded transition-colors" id="copy-config-btn">{{ t.copy }}</button>
+            <button onclick="copyConfig()" class="absolute top-2 {{ 'left-2' if lang == 'fa' else 'right-2' }} text-xs bg-gray-200 dark:bg-gray-700 hover:bg-gray-300 dark:hover:bg-gray-600 text-gray-600 dark:text-gray-300 px-3 py-1 rounded transition-colors" id="copy-config-btn">{{ t['copy'] }}</button>
         </div>
         {% else %}
         <p class="text-gray-500 dark:text-gray-400 text-sm">{{ t.no_sites }}. <a href="/dashboard/sites/add{% if lang and lang != 'en' %}?lang={{ lang }}{% endif %}" class="text-blue-600 dark:text-blue-400 hover:text-blue-500 dark:hover:text-blue-300">{{ t.add_site }}</a></p>
@@ -185,7 +185,7 @@ function copyConfig() {
     navigator.clipboard.writeText(text);
     const btn = document.getElementById('copy-config-btn');
     btn.textContent = '{{ t.copied }}';
-    setTimeout(() => btn.textContent = '{{ t.copy }}', 2000);
+    setTimeout(() => btn.textContent = '{{ t['copy'] }}', 2000);
 }
 
 // Load config on page load