chore: support configurable Go module proxy

scripts/verifyProxy.py

@@ -184,6 +184,7 @@ def main() -> None:
     parser = argparse.ArgumentParser(description=__doc__)
     parser.add_argument("--image", default="golang:1.25")
     parser.add_argument("--nginx-image", default="nginx:1.27-alpine")
+    parser.add_argument("--goproxy", default="", help="optional Go module proxy passed to the backend container")
     args = parser.parse_args()
     if shutil.which("docker") is None:
         raise SystemExit("docker is required for proxy verification")
@@ -203,13 +204,16 @@ def main() -> None:
         directory = Path(temporary)
         edge_port = free_port()
         write_edge_certificate(directory)
+        backend_command = [
+            "docker", "run", "--rm", "-i", "--pull=missing", "--name", backend_name,
+            "--network", "host", "--cpus=1", "--memory=512m", "--pids-limit=512",
+            "-v", f"{root}:/workspace", "-w", "/workspace", "-e", "GOWORK=off",
+        ]
+        if args.goproxy:
+            backend_command += ["-e", f"GOPROXY={args.goproxy}"]
+        backend_command += [args.image, "sh", "-c", "go run ./internal/perfcheck --server native --tls"]
         backend = subprocess.Popen(
-            [
-                "docker", "run", "--rm", "-i", "--pull=missing", "--name", backend_name,
-                "--network", "host", "--cpus=1", "--memory=512m", "--pids-limit=512",
-                "-v", f"{root}:/workspace", "-w", "/workspace", "-e", "GOWORK=off",
-                args.image, "sh", "-c", "go run ./internal/perfcheck --server native --tls",
-            ],
+            backend_command,
             stdin=subprocess.PIPE,
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE,