fix: tighten bonjour error coverage

src/infra/bonjour-errors.test.ts

@@ -8,6 +8,12 @@ describe("formatBonjourError", () => {
     expect(formatBonjourError(err)).toBe("AbortError: timed out");
   });
 
+  it("avoids duplicating named errors with blank messages", () => {
+    const err = new Error("");
+    err.name = "AbortError";
+    expect(formatBonjourError(err)).toBe("AbortError");
+  });
+
   it("falls back to plain error strings and non-error values", () => {
     expect(formatBonjourError(new Error(""))).toBe("Error");
     expect(formatBonjourError("boom")).toBe("boom");

src/infra/bonjour-errors.ts

@@ -1,7 +1,10 @@
 export function formatBonjourError(err: unknown): string {
   if (err instanceof Error) {
     const msg = err.message || String(err);
-    return err.name && err.name !== "Error" ? `${err.name}: ${msg}` : msg;
+    if (err.name && err.name !== "Error") {
+      return msg === err.name ? err.name : `${err.name}: ${msg}`;
+    }
+    return msg;
   }
   return String(err);
 }