fix(e2e): build frontend before tests (prevents wrong-app loading)

- onPrepare: run `npm run build` before `cargo tauri build --debug --no-bundle`
  (--no-bundle skips beforeBuildCommand, leaving no dist/ for the WebView)
- SKIP_BUILD: still verify dist/index.html exists, build frontend if missing
- Without this fix, the Tauri binary falls back to devUrl and loads whatever
  app is serving on that port (e.g., BridgeCoach on another project)

tests/e2e/wdio.conf.js

@@ -120,10 +120,23 @@ export const config = {
     }
 
     if (process.env.SKIP_BUILD) {
+      // Even with SKIP_BUILD, verify the frontend dist exists
+      if (!existsSync(resolve(projectRoot, 'dist/index.html'))) {
+        console.log('Frontend dist/ missing — building frontend only...');
+        execSync('npm run build', { cwd: projectRoot, stdio: 'inherit' });
+      }
       console.log('SKIP_BUILD set — using existing debug binary.');
       return Promise.resolve();
     }
-    return new Promise((resolve, reject) => {
+    return new Promise((resolveHook, reject) => {
+      // Build frontend first (Tauri --no-bundle skips beforeBuildCommand)
+      console.log('Building frontend...');
+      try {
+        execSync('npm run build', { cwd: projectRoot, stdio: 'inherit' });
+      } catch (e) {
+        reject(new Error(`Frontend build failed: ${e.message}`));
+        return;
+      }
       console.log('Building Tauri debug binary...');
       const build = spawn('cargo', ['tauri', 'build', '--debug', '--no-bundle'], {
         cwd: projectRoot,
@@ -132,7 +145,7 @@ export const config = {
       build.on('close', (code) => {
         if (code === 0) {
           console.log('Debug binary ready.');
-          resolve();
+          resolveHook();
         } else {
           reject(new Error(`Tauri build failed with exit code ${code}`));
         }