feat(admin): add styled buttons and session heartbeat

- Add StyledButtons.jsx component with gradient, copy, danger buttons
- Update Settings.jsx to use styled buttons throughout
- Improve JWT Key Generator UI with modern styled buttons
- Add session heartbeat to Initializer to prevent 401 token expiration
- Heartbeat pings /license/status every 4 minutes

Author: Schero94

admin/src/components/Initializer.jsx

@@ -1,10 +1,49 @@
-import { useEffect } from 'react';
+import { useEffect, useRef } from 'react';
+import { useFetchClient } from '@strapi/strapi/admin';
+import pluginId from '../pluginId';
+
+/**
+ * Initializer component that sets up the plugin and maintains session
+ * Includes a heartbeat to keep the admin session alive
+ */
+const Initializer = ({ setPlugin }) => {
+  const ref = useRef(setPlugin);
+  const { get } = useFetchClient();
 
-const Initializer = () => {
   useEffect(() => {
-    console.log('[magic-sessionmanager] Plugin initialized');
+    if (ref.current) {
+      ref.current(pluginId);
+    }
   }, []);
 
+  // Session heartbeat - keeps token alive by making periodic requests
+  useEffect(() => {
+    const HEARTBEAT_INTERVAL = 4 * 60 * 1000; // 4 minutes
+    
+    /**
+     * Sends a lightweight request to keep the session active
+     */
+    const heartbeat = async () => {
+      try {
+        // Use plugin's own license status endpoint as heartbeat (lightweight, authenticated)
+        await get(`/${pluginId}/license/status`);
+      } catch (error) {
+        // Silently ignore errors - this is just a keep-alive
+      }
+    };
+
+    // Initial heartbeat after 1 minute
+    const initialTimeout = setTimeout(heartbeat, 60 * 1000);
+    
+    // Regular heartbeat every 4 minutes
+    const interval = setInterval(heartbeat, HEARTBEAT_INTERVAL);
+
+    return () => {
+      clearTimeout(initialTimeout);
+      clearInterval(interval);
+    };
+  }, [get]);
+
   return null;
 };