feat: Migrate project to TypeScript by adding configuration, dependencies, and converting preload script.

src/main.ts

@@ -0,0 +1,64 @@
+import { app, BrowserWindow, ipcMain, dialog } from 'electron';
+import * as path from 'path';
+import * as fs from 'fs';
+
+function createWindow() {
+    const win = new BrowserWindow({
+        width: 1000,
+        height: 800,
+        webPreferences: {
+            preload: path.join(__dirname, 'preload.js'),
+            nodeIntegration: false,
+            contextIsolation: true,
+            sandbox: true
+        },
+        // Modern dark theme background
+        backgroundColor: '#0f172a',
+        titleBarStyle: 'hiddenInset' // Looks cleaner on macOS, normal on others
+    });
+
+    win.loadFile(path.join(__dirname, '../index.html'));
+    // Note: index.html is in the root, dist/main.js is in dist/. So we need to go up one level.
+}
+
+app.whenReady().then(() => {
+    createWindow();
+
+    app.on('activate', () => {
+        if (BrowserWindow.getAllWindows().length === 0) {
+            createWindow();
+        }
+    });
+});
+
+app.on('window-all-closed', () => {
+    if (process.platform !== 'darwin') {
+        app.quit();
+    }
+});
+
+ipcMain.handle('open-file-dialog', async () => {
+    const { canceled, filePaths } = await dialog.showOpenDialog({
+        properties: ['openFile'],
+        filters: [
+            { name: 'Markdown', extensions: ['md', 'markdown', 'txt'] },
+            { name: 'All Files', extensions: ['*'] }
+        ]
+    });
+
+    if (canceled) {
+        return null;
+    } else {
+        return filePaths[0];
+    }
+});
+
+ipcMain.handle('read-file', async (event, filePath: string) => {
+    try {
+        const content = fs.readFileSync(filePath, 'utf-8');
+        return content;
+    } catch (err) {
+        console.error("Error reading file", err);
+        throw err;
+    }
+});