test(daemon-server): bind blocker to 0.0.0.0 so EADDRINUSE fires on macOS/Windows

Previous version bound the blocker to 127.0.0.1, but express.listen(port)
binds to 0.0.0.0 (no host arg). On BSD-derived stacks (macOS, Windows) a
127.0.0.1 bind and a 0.0.0.0 bind on the same port can coexist, so the
daemon's wildcard listen succeeded and the test asserted rejection but got
a resolved promise. Linux is stricter and treats this as a conflict, which
is why ubuntu passed but the other runners failed.

Author: Rinse12

test/webui/daemon-server.test.ts

@@ -11,6 +11,11 @@ import { startDaemonServer } from "../../dist/webui/daemon-server.js";
 // The contract we want: if the port can't be bound, startDaemonServer must reject.
 describe("startDaemonServer bind contract", () => {
     it("rejects when the RPC port is already taken (regression for issue #42)", async () => {
+        // Blocker must bind to 0.0.0.0 because express.listen(port) (no host arg) also
+        // binds to 0.0.0.0. On BSD-derived stacks (macOS, Windows) a wildcard bind and
+        // a 127.0.0.1 bind on the same port can coexist, so binding the blocker to
+        // 127.0.0.1 would let the daemon's wildcard bind succeed and the test wouldn't
+        // exercise the EADDRINUSE path.
         const blocker = net.createServer();
         const port = await new Promise<number>((resolve, reject) => {
             blocker.once("listening", () => {
@@ -19,7 +24,7 @@ describe("startDaemonServer bind contract", () => {
                 else reject(new Error(`unexpected address ${JSON.stringify(addr)}`));
             });
             blocker.once("error", reject);
-            blocker.listen(0, "127.0.0.1");
+            blocker.listen(0, "0.0.0.0");
         });
 
         // Swallow any stray uncaughtException emitted by an unguarded server.listen()