fix: pass electron version explicitly to electron-rebuild on Windows (#622)

Issue:
On Windows, running `npm run install:all` failed during the frontend
postinstall step. The electron-rebuild command couldn't auto-detect
Electron's version, failing with: "Unable to find electron's version
number, either install it or specify an explicit version"

Solution:
Added a `getElectronVersion()` helper function that reads the Electron
version from package.json's devDependencies and passes it explicitly
to electron-rebuild via the `-v` flag. This ensures the rebuild works
correctly even when version auto-detection fails.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Andy <119136210+AndyMik90@users.noreply.github.com>

apps/frontend/scripts/postinstall.cjs

@@ -42,13 +42,36 @@ To install:
 ================================================================================
 `;
 
+/**
+ * Get electron version from package.json
+ */
+function getElectronVersion() {
+  const pkgPath = path.join(__dirname, '..', 'package.json');
+  const pkg = JSON.parse(fs.readFileSync(pkgPath, 'utf8'));
+  const electronVersion = pkg.devDependencies?.electron || pkg.dependencies?.electron;
+  if (!electronVersion) {
+    return null;
+  }
+  // Strip leading ^ or ~ from version
+  return electronVersion.replace(/^[\^~]/, '');
+}
+
 /**
  * Run electron-rebuild
  */
 function runElectronRebuild() {
   return new Promise((resolve, reject) => {
     const npx = isWindows ? 'npx.cmd' : 'npx';
-    const child = spawn(npx, ['electron-rebuild'], {
+    const electronVersion = getElectronVersion();
+    const args = ['electron-rebuild'];
+
+    // Explicitly pass electron version if detected
+    if (electronVersion) {
+      args.push('-v', electronVersion);
+      console.log(`[postinstall] Using Electron version: ${electronVersion}`);
+    }
+
+    const child = spawn(npx, args, {
       stdio: 'inherit',
       shell: isWindows,
       cwd: path.join(__dirname, '..'),