refactor: switch admin create_queue from protobuf to binary encoding

src/test/java/dev/faisca/fila/FibpAdminClient.java

@@ -19,9 +19,8 @@
 /**
  * Minimal FIBP admin client for test infrastructure.
  *
- * <p>Supports CreateQueue only. Admin operation payloads are protobuf-encoded (matching the
- * server's fila-core admin dispatch). We hand-roll the minimal protobuf needed to avoid a test
- * dependency on a protobuf runtime.
+ * <p>Supports CreateQueue only. Admin operation payloads use binary encoding (same wire format as
+ * data ops).
  *
  * <p>Supports both plaintext and TLS/mTLS connections.
  */
@@ -133,26 +132,36 @@ private void authenticate(String apiKey) throws IOException {
   }
 
   /**
-   * Encode a CreateQueueRequest protobuf message with just the name field.
+   * Encode a CreateQueue request using the binary wire format.
    *
-   * <p>Protobuf encoding: field 1 (name, string) = tag 0x0A (field=1, wire_type=2) + varint(len) +
-   * utf8 bytes.
+   * <p>Wire format: queue_len:u16 + queue:utf8 + on_enqueue_len:u16 + on_enqueue:utf8 +
+   * on_failure_len:u16 + on_failure:utf8 + visibility_timeout_ms:u32
    */
-  private static byte[] encodeCreateQueueRequest(String name) {
+  private static byte[] encodeCreateQueueRequest(String name) throws IOException {
     byte[] nameBytes = name.getBytes(StandardCharsets.UTF_8);
+    if (nameBytes.length > 0xFFFF) {
+      throw new IOException(
+          "queue name too long: UTF-8 length " + nameBytes.length + " exceeds u16 max (65535)");
+    }
     ByteArrayOutputStream buf = new ByteArrayOutputStream();
-    buf.write(0x0A); // field 1, wire type 2 (length-delimited)
-    writeVarint(buf, nameBytes.length);
+    writeU16(buf, nameBytes.length);
     buf.write(nameBytes, 0, nameBytes.length);
+    writeU16(buf, 0); // on_enqueue: empty
+    writeU16(buf, 0); // on_failure: empty
+    writeU32(buf, 0); // visibility_timeout_ms: 0
     return buf.toByteArray();
   }
 
-  private static void writeVarint(ByteArrayOutputStream buf, int value) {
-    while ((value & ~0x7F) != 0) {
-      buf.write((value & 0x7F) | 0x80);
-      value >>>= 7;
-    }
-    buf.write(value);
+  private static void writeU16(ByteArrayOutputStream buf, int value) {
+    buf.write((value >> 8) & 0xFF);
+    buf.write(value & 0xFF);
+  }
+
+  private static void writeU32(ByteArrayOutputStream buf, int value) {
+    buf.write((value >> 24) & 0xFF);
+    buf.write((value >> 16) & 0xFF);
+    buf.write((value >> 8) & 0xFF);
+    buf.write(value & 0xFF);
   }
 
   private static KeyManagerFactory buildKeyManagerFactory(byte[] certPem, byte[] keyPem)