Served with isolation headers; start-screen capability notices; tests on the real GPU (t88 phase 1)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/caps.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+"""Print isolation, WebGPU adapter info and GL renderer for installed browsers."""
+import argparse
+import json
+
+from use_venv import ensure_playwright
+ensure_playwright()
+from browser import capabilities, gpu_option, installed, launch
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    gpu_option(parser)
+    options = parser.parse_args()
+    for name in ['chromium', 'firefox']:
+        if not installed(name):
+            print(f'SKIP {name}: Playwright browser is not installed')
+            continue
+        with launch(gpu=options.gpu, browser_name=name) as (browser, page, url):
+            page.goto(url)
+            caps = capabilities(page)
+            print(f'{name} {browser.version}: {json.dumps(caps)}', flush=True)
+            assert caps['isolated'], 'Server did not isolate the page'
+            if name == 'chromium' and options.gpu == 'real':
+                assert caps['webgpu'] and caps['adapterInfo'] is not None, 'No headless WebGPU adapter'
+                assert caps['adapterInfo']['architecture'] != 'swiftshader', 'Software WebGPU in real mode'
+                assert not any(s in (caps['renderer'] or '').lower() for s in ['swiftshader', 'llvmpipe', 'softpipe']), 'Software GL in real mode'
+
+
+if __name__ == '__main__':
+    main()