feat: add Electron desktop application support

- Add electron/ directory with main process, preload script, and types
- Add system tray integration and window management
- Add IPC communication for app info, external links, server controls
- Add useElectron React hooks for Next.js integration
- Add build scripts for Windows, macOS, and Linux
- Add development scripts for running Electron with Next.js

Ref: #149

src/shared/hooks/useElectron.ts

@@ -0,0 +1,192 @@
+'use client';
+
+import { useState, useEffect, useCallback } from 'react';
+
+/**
+ * Check if the app is running in Electron
+ */
+export function useIsElectron(): boolean {
+  const [isElectron, setIsElectron] = useState(false);
+
+  useEffect(() => {
+    setIsElectron(typeof window !== 'undefined' && window.electronAPI?.isElectron === true);
+  }, []);
+
+  return isElectron;
+}
+
+/**
+ * Get Electron app information
+ */
+export function useElectronAppInfo() {
+  const [appInfo, setAppInfo] = useState<{
+    name: string;
+    version: string;
+    platform: string;
+    isDev: boolean;
+    port: number;
+  } | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<Error | null>(null);
+
+  useEffect(() => {
+    if (typeof window === 'undefined' || !window.electronAPI) {
+      setLoading(false);
+      return;
+    }
+
+    window.electronAPI
+      .getAppInfo()
+      .then((info) => {
+        setAppInfo(info);
+        setLoading(false);
+      })
+      .catch((err) => {
+        setError(err);
+        setLoading(false);
+      });
+  }, []);
+
+  return { appInfo, loading, error };
+}
+
+/**
+ * Get the data directory path
+ */
+export function useDataDir() {
+  const [dataDir, setDataDir] = useState<string | null>(null);
+  const [loading, setLoading] = useState(true);
+
+  useEffect(() => {
+    if (typeof window === 'undefined' || !window.electronAPI) {
+      setLoading(false);
+      return;
+    }
+
+    window.electronAPI
+      .getDataDir()
+      .then((dir) => {
+        setDataDir(dir);
+        setLoading(false);
+      })
+      .catch(() => {
+        setLoading(false);
+      });
+  }, []);
+
+  return { dataDir, loading };
+}
+
+/**
+ * Window controls for Electron
+ */
+export function useWindowControls() {
+  const isElectron = useIsElectron();
+
+  const minimize = useCallback(() => {
+    if (isElectron && window.electronAPI) {
+      window.electronAPI.minimizeWindow();
+    }
+  }, [isElectron]);
+
+  const maximize = useCallback(() => {
+    if (isElectron && window.electronAPI) {
+      window.electronAPI.maximizeWindow();
+    }
+  }, [isElectron]);
+
+  const close = useCallback(() => {
+    if (isElectron && window.electronAPI) {
+      window.electronAPI.closeWindow();
+    }
+  }, [isElectron]);
+
+  return {
+    isElectron,
+    minimize,
+    maximize,
+    close,
+  };
+}
+
+/**
+ * Open external URL in default browser
+ */
+export function useOpenExternal() {
+  const isElectron = useIsElectron();
+
+  const openExternal = useCallback(
+    async (url: string) => {
+      if (isElectron && window.electronAPI) {
+        await window.electronAPI.openExternal(url);
+      } else {
+        window.open(url, '_blank', 'noopener,noreferrer');
+      }
+    },
+    [isElectron]
+  );
+
+  return { openExternal };
+}
+
+/**
+ * Server controls for Electron
+ */
+export function useServerControls() {
+  const isElectron = useIsElectron();
+  const [restarting, setRestarting] = useState(false);
+
+  const restart = useCallback(async () => {
+    if (!isElectron || !window.electronAPI) {
+      return { success: false };
+    }
+
+    setRestarting(true);
+    try {
+      const result = await window.electronAPI.restartServer();
+      return result;
+    } finally {
+      setRestarting(false);
+    }
+  }, [isElectron]);
+
+  return {
+    isElectron,
+    restart,
+    restarting,
+  };
+}
+
+/**
+ * Listen for server status updates
+ */
+export function useServerStatus(onStatus: (status: { status: string; port: number }) => void) {
+  const isElectron = useIsElectron();
+
+  useEffect(() => {
+    if (!isElectron || !window.electronAPI) return;
+
+    window.electronAPI.onServerStatus(onStatus);
+
+    return () => {
+      window.electronAPI.removeServerStatusListener();
+    };
+  }, [isElectron, onStatus]);
+}
+
+/**
+ * Listen for port changes
+ */
+export function usePortChanged(onPortChanged: (port: number) => void) {
+  const isElectron = useIsElectron();
+
+  useEffect(() => {
+    if (!isElectron || !window.electronAPI) return;
+
+    window.electronAPI.onPortChanged(onPortChanged);
+
+    return () => {
+      window.electronAPI.removePortChangedListener();
+    };
+  }, [isElectron, onPortChanged]);
+}