feat: unified E2E testing engine — 205 tests, dual-stack support

Infrastructure:
- adapters/: base, tauri (port 9750), electrobun (port 9761 + PTY daemon)
- helpers/: 120+ centralized selectors, reusable actions, custom assertions
- wdio.shared.conf.js + stack-specific configs

18 unified specs (205 tests):
splash(6) smoke(15) settings(19) terminal(14) agent(15) search(12)
files(15) comms(10) tasks(10) theme(12) groups(12) keyboard(8)
notifications(10) diagnostics(8) status-bar(12) context(9)
worktree(8) llm-judged(10)

Daemon: --stack tauri|electrobun|both flag
Scripts: test:e2e:tauri, test:e2e:electrobun, test:e2e:both

tests/e2e/wdio.electrobun.conf.js

@@ -0,0 +1,90 @@
+/**
+ * WebDriverIO config for Electrobun stack E2E tests.
+ *
+ * Extends shared config with WebKitWebDriver lifecycle and optional
+ * PTY daemon management. Port: 9761 (per project convention).
+ */
+
+import { execSync } from 'node:child_process';
+import { resolve, dirname } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { existsSync, rmSync } from 'node:fs';
+import { sharedConfig } from './wdio.shared.conf.js';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const projectRoot = resolve(__dirname, '../..');
+const electrobunRoot = resolve(projectRoot, 'ui-electrobun');
+
+// Use the Electrobun fixture generator (different groups.json format)
+let fixture;
+try {
+  const { createTestFixture } = await import('../../ui-electrobun/tests/e2e/fixtures.ts');
+  fixture = createTestFixture('agor-ebun-unified');
+} catch {
+  // Fall back to the Tauri fixture generator if Electrobun fixtures not available
+  const { createTestFixture } = await import('./infra/fixtures.ts');
+  fixture = createTestFixture('agor-ebun-unified');
+}
+
+process.env.AGOR_TEST = '1';
+process.env.AGOR_TEST_DATA_DIR = fixture.dataDir;
+process.env.AGOR_TEST_CONFIG_DIR = fixture.configDir;
+
+const WEBDRIVER_PORT = 9761;
+
+console.log(`[electrobun] Test fixture at ${fixture.rootDir ?? fixture.configDir}`);
+
+export const config = {
+  ...sharedConfig,
+
+  port: WEBDRIVER_PORT,
+
+  capabilities: [{
+    'wdio:enforceWebDriverClassic': true,
+    browserName: 'webkit',
+  }],
+
+  onPrepare() {
+    const electrobunBinary = resolve(electrobunRoot, 'build/Agent Orchestrator');
+
+    if (!existsSync(electrobunBinary) && !process.env.SKIP_BUILD) {
+      console.log('Building Electrobun canary...');
+      execSync('vite build && electrobun build --env=canary', {
+        cwd: electrobunRoot,
+        stdio: 'inherit',
+      });
+    }
+
+    if (!existsSync(electrobunBinary)) {
+      throw new Error(
+        `Electrobun binary not found at ${electrobunBinary}. ` +
+        "Run 'cd ui-electrobun && bun run build:canary' first."
+      );
+    }
+  },
+
+  async before() {
+    // Wait for Electrobun app to load
+    await browser.waitUntil(
+      async () => {
+        const hasEl = await browser.execute(() =>
+          document.querySelector('.app-shell') !== null
+          || document.querySelector('.project-grid') !== null
+          || document.querySelector('.status-bar') !== null
+        );
+        return hasEl;
+      },
+      { timeout: 20_000, interval: 500, timeoutMsg: 'Electrobun app did not load in 20s' },
+    );
+    console.log('[electrobun] App loaded.');
+  },
+
+  afterSession() {
+    const cleanup = fixture.cleanup ?? (() => {
+      try {
+        if (fixture.rootDir) rmSync(fixture.rootDir, { recursive: true, force: true });
+      } catch { /* best-effort */ }
+    });
+    cleanup();
+  },
+};