Add E2E test for terminal copy selection

Verifies that selecting text in the terminal and releasing the mouse
correctly copies the selection to clipboard. The test confirms the
mouseup → copySelection flow works without interference from the
click → focus handler.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

e2e/tests/tmux-terminal.spec.ts

@@ -1,4 +1,4 @@
-import { test, expect } from '@playwright/test';
+import { test, expect, type BrowserContext } from '@playwright/test';
 import { E2E_BACKEND_URL } from '../playwright.config';
 
 // Helper to delete a specific session by ID via API
@@ -182,6 +182,92 @@ test.describe('Tmux Terminal Session', () => {
     console.log('[Test] Tmux session properly cleaned up');
   });
 
+  test('copy selection from terminal works', async ({ page, request, context }) => {
+    // Grant clipboard permissions
+    await context.grantPermissions(['clipboard-read', 'clipboard-write']);
+
+    // Track session ID for cleanup
+    let createdSessionId: string | null = null;
+
+    // 1. Navigate to homepage and create a tmux session
+    await page.goto('/');
+    const createButton = page.locator('button[title="New Session"]');
+    await createButton.click();
+
+    const tmuxOption = page.locator('button:has-text("Terminal (tmux)")');
+    await tmuxOption.click();
+
+    // Wait for navigation to session page
+    await page.waitForURL(/\/session\/.+/);
+    const sessionUrl = page.url();
+    createdSessionId = decodeURIComponent(sessionUrl.split('/session/')[1]);
+    console.log('[Test] Created session:', createdSessionId);
+
+    // 2. Wait for terminal to load
+    const terminalOutput = page.locator('pre.text-green-400');
+    await expect(terminalOutput).toBeVisible({ timeout: 10000 });
+
+    // 3. Run a command with unique output
+    const uniqueMarker = `COPY-TEST-${Date.now()}`;
+    const commandInput = page.locator('input[aria-label="Terminal input"]');
+    await expect(commandInput).toBeEnabled({ timeout: 5000 });
+    await commandInput.focus();
+    await page.keyboard.type(`echo "${uniqueMarker}"`);
+    await page.keyboard.press('Enter');
+    console.log('[Test] Sent echo command with marker:', uniqueMarker);
+
+    // Wait for output
+    await expect(async () => {
+      const content = await terminalOutput.textContent();
+      expect(content).toContain(uniqueMarker);
+    }).toPass({ timeout: 5000 });
+    console.log('[Test] Marker appeared in terminal');
+
+    // 4. Clear the clipboard first
+    await page.evaluate(() => navigator.clipboard.writeText(''));
+
+    // 5. Select the marker text by triple-clicking on the line containing it
+    // First, find the position of the marker in the terminal
+    const terminalBox = await terminalOutput.boundingBox();
+    expect(terminalBox).not.toBeNull();
+
+    // Get the terminal content to find the marker position
+    const content = await terminalOutput.textContent();
+    const lines = content?.split('\n') || [];
+    const markerLineIndex = lines.findIndex(line => line.includes(uniqueMarker) && !line.includes('echo'));
+    console.log('[Test] Marker found on line index:', markerLineIndex);
+
+    if (markerLineIndex >= 0 && terminalBox) {
+      // Calculate approximate Y position of the marker line
+      // Assuming ~20px per line (adjust based on actual font size)
+      const lineHeight = 20;
+      const yOffset = markerLineIndex * lineHeight + lineHeight / 2 + 12; // +12 for padding
+
+      // Triple-click to select the entire line
+      await page.mouse.click(terminalBox.x + 50, terminalBox.y + yOffset, { clickCount: 3 });
+      console.log('[Test] Triple-clicked to select line at y offset:', yOffset);
+
+      // Give a moment for the selection to register and copy to happen
+      await page.waitForTimeout(200);
+
+      // 6. Verify clipboard contains the marker
+      const clipboardContent = await page.evaluate(() => navigator.clipboard.readText());
+      console.log('[Test] Clipboard content:', clipboardContent);
+
+      // The clipboard should contain the marker (the entire line might be selected)
+      expect(clipboardContent).toContain(uniqueMarker);
+      console.log('[Test] Copy selection test passed - clipboard contains marker');
+    } else {
+      throw new Error(`Could not find marker line in terminal output`);
+    }
+
+    // 7. Cleanup
+    if (createdSessionId) {
+      await deleteSession(request, createdSessionId);
+    }
+    console.log('[Test] Cleanup complete');
+  });
+
   test('eject tmux session removes from spiceflow but keeps tmux running', async ({ page, request }) => {
     // Track session ID for cleanup
     let createdSessionId: string | null = null;