fix(e2e): cross-protocol browser.execute() — works with both WebDriver + CDP

Root cause: WebDriverIO devtools protocol wraps functions in a polyfill
that puts `return` inside eval() (not a function body) → "Illegal return".

Fix: exec() wrapper in helpers/execute.ts converts function args to IIFE
strings before passing to browser.execute(). Works identically on both
WebDriver (Tauri) and CDP/devtools (Electrobun CEF).

- 35 spec files updated (browser.execute → exec)
- 4 config files updated (string-form expressions)
- helpers/actions.ts + assertions.ts updated
- 560 vitest + 116 cargo passing

tests/e2e/specs/diagnostics.test.ts

@@ -8,10 +8,11 @@
 import { browser, expect } from '@wdio/globals';
 import * as S from '../helpers/selectors.ts';
 import { openSettings, closeSettings, switchSettingsCategory } from '../helpers/actions.ts';
+import { exec } from '../helpers/execute.ts';
 
 /** Navigate to the last settings tab (expected to be Diagnostics on Electrobun) */
 async function navigateToLastTab(): Promise<number> {
-  const tabCount = await browser.execute(() => {
+  const tabCount = await exec(() => {
     return (document.querySelectorAll('.settings-sidebar .sidebar-item').length
       || document.querySelectorAll('.settings-tab').length
       || document.querySelectorAll('.cat-btn').length);
@@ -34,7 +35,7 @@ describe('Diagnostics tab', () => {
   });
 
   it('should render the diagnostics container', async function () {
-    const exists = await browser.execute((sel: string) => {
+    const exists = await exec((sel: string) => {
       return document.querySelector(sel) !== null;
     }, S.DIAGNOSTICS);
     if (!exists) {
@@ -47,12 +48,12 @@ describe('Diagnostics tab', () => {
   });
 
   it('should show Transport Diagnostics heading', async function () {
-    const exists = await browser.execute(() => {
+    const exists = await exec(() => {
       return document.querySelector('.diagnostics') !== null;
     });
     if (!exists) { this.skip(); return; }
 
-    const text = await browser.execute((sel: string) => {
+    const text = await exec((sel: string) => {
       const el = document.querySelector(sel);
       return el?.textContent ?? '';
     }, S.DIAG_HEADING);
@@ -62,12 +63,12 @@ describe('Diagnostics tab', () => {
   });
 
   it('should show PTY daemon connection status', async function () {
-    const exists = await browser.execute(() => {
+    const exists = await exec(() => {
       return document.querySelector('.diagnostics') !== null;
     });
     if (!exists) { this.skip(); return; }
 
-    const texts = await browser.execute((sel: string) => {
+    const texts = await exec((sel: string) => {
       const keys = document.querySelectorAll(sel);
       return Array.from(keys).map(k => k.textContent ?? '');
     }, S.DIAG_KEY);
@@ -77,12 +78,12 @@ describe('Diagnostics tab', () => {
   });
 
   it('should show agent fleet section', async function () {
-    const exists = await browser.execute(() => {
+    const exists = await exec(() => {
       return document.querySelector('.diagnostics') !== null;
     });
     if (!exists) { this.skip(); return; }
 
-    const texts = await browser.execute((sel: string) => {
+    const texts = await exec((sel: string) => {
       const labels = document.querySelectorAll(sel);
       return Array.from(labels).map(l => l.textContent?.toLowerCase() ?? '');
     }, S.DIAG_LABEL);
@@ -92,12 +93,12 @@ describe('Diagnostics tab', () => {
   });
 
   it('should show last refresh timestamp', async function () {
-    const exists = await browser.execute(() => {
+    const exists = await exec(() => {
       return document.querySelector('.diagnostics') !== null;
     });
     if (!exists) { this.skip(); return; }
 
-    const footerExists = await browser.execute((sel: string) => {
+    const footerExists = await exec((sel: string) => {
       return document.querySelector(sel) !== null;
     }, S.DIAG_FOOTER);
     if (footerExists) {
@@ -107,7 +108,7 @@ describe('Diagnostics tab', () => {
   });
 
   it('should have a refresh button', async function () {
-    const exists = await browser.execute(() => {
+    const exists = await exec(() => {
       return document.querySelector('.diagnostics') !== null;
     });
     if (!exists) { this.skip(); return; }
@@ -119,12 +120,12 @@ describe('Diagnostics tab', () => {
   });
 
   it('should show connection indicator with color', async function () {
-    const exists = await browser.execute(() => {
+    const exists = await exec(() => {
       return document.querySelector('.diagnostics') !== null;
     });
     if (!exists) { this.skip(); return; }
 
-    const hasIndicator = await browser.execute(() => {
+    const hasIndicator = await exec(() => {
       return (document.querySelector('.diag-status')
         ?? document.querySelector('.status-dot')
         ?? document.querySelector('.connection-status')) !== null;
@@ -133,12 +134,12 @@ describe('Diagnostics tab', () => {
   });
 
   it('should show session count', async function () {
-    const exists = await browser.execute(() => {
+    const exists = await exec(() => {
       return document.querySelector('.diagnostics') !== null;
     });
     if (!exists) { this.skip(); return; }
 
-    const hasCount = await browser.execute(() => {
+    const hasCount = await exec(() => {
       return (document.querySelector('.session-count')
         ?? document.querySelector('.diag-value')) !== null;
     });