fix(bonjour): harden DNS label truncation

extensions/bonjour/src/advertiser.test.ts

@@ -736,7 +736,7 @@ describe("gateway bonjour advertiser", () => {
   });
 
   it("truncates service name exceeding 63-byte DNS label limit", async () => {
-    const longHostname = "app-41627eae5842473f9e05f139ea307277-7f9477f4d6-lqqzf";
+    const longHostname = "app-41627eae5842473f9e05f139ea307277-7f9477f4d6-lqqzf-abcdefghi";
     enableAdvertiserUnitMode(longHostname);
 
     const destroy = vi.fn().mockResolvedValue(undefined);
@@ -755,6 +755,7 @@ describe("gateway bonjour advertiser", () => {
     // Both name and hostname must be within the 63-byte DNS label limit
     expect(new TextEncoder().encode(serviceName).byteLength).toBeLessThanOrEqual(63);
     expect(new TextEncoder().encode(hostname).byteLength).toBeLessThanOrEqual(63);
+    expect(hostname).not.toMatch(/-$/);
 
     await started.stop();
   });

extensions/bonjour/src/advertiser.ts

@@ -185,7 +185,7 @@ function resolveSystemMdnsHostname(): string | null {
 
 const MAX_DNS_LABEL_BYTES = 63;
 
-function truncateToDnsLabel(name: string): string {
+function truncateToDnsLabel(name: string, fallback = "OpenClaw"): string {
   const encoder = new TextEncoder();
   const encoded = encoder.encode(name);
   if (encoded.byteLength <= MAX_DNS_LABEL_BYTES) {
@@ -195,7 +195,12 @@ function truncateToDnsLabel(name: string): string {
   const truncated = encoded.slice(0, MAX_DNS_LABEL_BYTES);
   const decoded = new TextDecoder("utf-8", { fatal: false }).decode(truncated);
   // Strip any replacement character from incomplete multi-byte sequence at the end
-  return decoded.replace(/\uFFFD$/, "").trim() || "OpenClaw";
+  return (
+    decoded
+      .replace(/\uFFFD$/, "")
+      .replace(/-+$/, "")
+      .trim() || fallback
+  );
 }
 
 function safeServiceName(name: string) {
@@ -373,6 +378,7 @@ export async function startGatewayBonjourAdvertiser(
         .replace(/\.local$/i, "")
         .split(".")[0]
         .trim() || "openclaw",
+      "openclaw",
     );
     const instanceName =
       typeof opts.instanceName === "string" && opts.instanceName.trim()