fix(ci): harden llm-test mock HTTP server against stalled connections

llm-test

@@ -46,10 +46,14 @@ for f in lib/*.llm; do
     fi
 done
 
-# Start background mock HTTP server for standard library testing
+# Start background mock HTTP server for standard library testing.
+# ThreadingHTTPServer + a per-connection timeout so a stray idle connection
+# (e.g. a port prober on CI runners) cannot wedge the accept loop and stall
+# real requests behind it.
 python3 -c '
-from http.server import HTTPServer, BaseHTTPRequestHandler
+from http.server import ThreadingHTTPServer, BaseHTTPRequestHandler
 class Handler(BaseHTTPRequestHandler):
+    timeout = 5
     def log_message(self, format, *args):
         pass
     def do_GET(self):
@@ -64,7 +68,8 @@ class Handler(BaseHTTPRequestHandler):
         self.send_header("Content-Type", "text/plain")
         self.end_headers()
         self.wfile.write(b"Echo: " + body)
-server = HTTPServer(("127.0.0.1", 8080), Handler)
+server = ThreadingHTTPServer(("127.0.0.1", 8080), Handler)
+server.daemon_threads = True
 server.serve_forever()
 ' >/dev/null 2>&1 &
 MOCK_PID=$!
@@ -76,8 +81,19 @@ cleanup() {
 }
 trap cleanup EXIT
 
-# Wait a brief moment for the server to bind
-sleep 0.5
+# Wait until the mock server is actually answering requests (up to 10s)
+SERVER_READY=false
+for _ in $(seq 1 40); do
+    if curl -s --max-time 1 http://127.0.0.1:8080/ 2>/dev/null | grep -q "Hello from local mock server"; then
+        SERVER_READY=true
+        break
+    fi
+    sleep 0.25
+done
+if [ "$SERVER_READY" = false ]; then
+    echo "WARNING: mock HTTP server on 127.0.0.1:8080 is not responding; port state:"
+    lsof -nP -i :8080 2>/dev/null || true
+fi
 
 echo "Running llmlang self-hosted tests..."
 echo "------------------------------------"