feat: add electron context bridge (#14)

electron/preload/index.ts

@@ -1 +1,13 @@
-console.log("---- electron/preload.ts ----");
+import { contextBridge, shell } from "electron";
+import fs from "node:fs";
+
+import { IElectronAPI } from "../../src/types/global";
+
+const Api: IElectronAPI = {
+  fileExists: fs.existsSync,
+  getPlatform: () => process.platform,
+  openFile: shell.openPath,
+  showFile: shell.showItemInFolder,
+};
+
+contextBridge.exposeInMainWorld("electronAPI", Api);

src/types/global.d.ts

@@ -0,0 +1,12 @@
+export interface IElectronAPI {
+  fileExists: (path: string) => boolean;
+  getPlatform: () => string;
+  openFile: (path: string) => Promise<string>;
+  showFile: (path: string) => void;
+}
+
+declare global {
+  interface Window {
+    electronAPI?: IElectronAPI;
+  }
+}