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/server.py

@@ -1,5 +1,6 @@
 """Serve dist/ with isolation headers; isolated_server() owns a free-port background server."""
 from contextlib import contextmanager
+from functools import partial
 from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
 from pathlib import Path
 from threading import Thread
@@ -8,8 +9,8 @@ DIST = Path(__file__).resolve().parent.parent / 'dist'
 
 
 class Handler(SimpleHTTPRequestHandler):
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, directory=str(DIST), **kwargs)
+    def __init__(self, *args, directory=DIST, **kwargs):
+        super().__init__(*args, directory=str(directory), **kwargs)
 
     def end_headers(self):
         self.send_header('Cache-Control', 'no-store')
@@ -22,8 +23,8 @@ class Handler(SimpleHTTPRequestHandler):
 
 
 @contextmanager
-def isolated_server():
-    with ThreadingHTTPServer(('127.0.0.1', 0), Handler) as server:
+def isolated_server(directory=DIST):
+    with ThreadingHTTPServer(('127.0.0.1', 0), partial(Handler, directory=directory)) as server:
         thread = Thread(target=server.serve_forever, daemon=True)
         thread.start()
         try: