The body should be annotated with `Any`, because the request and the response would be... well... **anything**. 🤷

The idea is that you would receive the payload and send it **directly** to an LLM provider, using a `prompt` to tell the LLM what to do, and return the response **as is**. No questions asked.

## What we expect from contributors

        history.add(LlmMessage.user("How to install Fess?"));
        history.add(LlmMessage.assistant("You can install Fess using Docker."));
        final LlmChatRequest request = client.testBuildIntentRequest("Tell me more about Docker", history);
        final List<LlmMessage> messages = request.getMessages();
        // system + 2 history + user = 4 messages
        assertEquals(4, messages.size());

   *
   * <p>Note that a method may still be effectively "final", or non-overridable when it has no
   * {@code final} keyword. For example, it could be private, or it could be declared by a final
   * class. To tell whether a method is overridable, use {@link Invokable#isOverridable}.
   */
  public final boolean isFinal() {
    return Modifier.isFinal(getModifiers());
  }

  /** Returns true if the method is abstract. */

  private static class WithTypeVariable {

    @SuppressWarnings("unused")
    <T> void withoutBound(List<T> list) {}

    @SuppressWarnings({
      "unused",
      /*
       * Since reflection can't tell the difference between <T> and <T extends Object>, it doesn't
       * make a ton of sense to have a separate tests for each. But having tests for each doesn't

        br.addItem("Limit Size");
        br.addElement(limitSize);
        final String msg = br.buildExceptionMessage();
        throw new Forced404NotFoundException(msg, UserMessages.empty()); // heavy attack!? so give no page to tell wasted action
    }

    protected void setupServletFileUpload(final JakartaServletDiskFileUpload upload, final HttpServletRequest request) {
        upload.setHeaderCharset(Charset.forName(request.getCharacterEncoding()));

         * only possible value for the type parameter is <E>, since otherwise the
         * MultiExceptionListIterator wouldn't be an Iterator<E>. The cast is safe, even though
         * javac can't tell.
         */
        @SuppressWarnings("unchecked")
        MultiExceptionListIterator multiExceptionListIterator =
            (MultiExceptionListIterator) reference;

         * only possible value for the type parameter is <E>, since otherwise the
         * MultiExceptionListIterator wouldn't be an Iterator<E>. The cast is safe, even though
         * javac can't tell.
         */
        @SuppressWarnings("unchecked")
        MultiExceptionListIterator multiExceptionListIterator =
            (MultiExceptionListIterator) reference;

   * or resource constraints) accept without blocking. This is always equal to the initial capacity
   * of this queue less the current {@code size} of this queue.
   *
   * <p>Note that you cannot always tell if an attempt to insert an element will succeed by
   * inspecting {@code remainingCapacity} because it may be the case that another thread is about to
   * insert or remove an element.
   */
  @CanIgnoreReturnValue

   * or resource constraints) accept without blocking. This is always equal to the initial capacity
   * of this queue less the current {@code size} of this queue.
   *
   * <p>Note that you cannot always tell if an attempt to insert an element will succeed by
   * inspecting {@code remainingCapacity} because it may be the case that another thread is about to
   * insert or remove an element.
   */
  @CanIgnoreReturnValue