Allow image-only visitor messages

public/admin.js

@@ -69,21 +69,28 @@ $("#settingsForm").addEventListener("submit", async (event) => {
 $("#replyForm").addEventListener("submit", async (event) => {
   event.preventDefault();
   if (!state.activeId) return;
+  const textarea = event.currentTarget.querySelector("textarea[name='message']");
+  const originalMessage = textarea.value;
   const form = new FormData(event.currentTarget);
   const payload = {
     message: form.get("message") || "",
     attachments: await Promise.all(state.replyFiles.slice(0, 3).map(fileToPayload))
   };
   if (!payload.message.trim() && !payload.attachments.length) return;
-  await api(`/api/admin/conversations/${state.activeId}/messages`, {
-    method: "POST",
-    body: payload
-  });
-  event.currentTarget.querySelector("textarea[name='message']").value = "";
-  event.currentTarget.reset();
-  state.replyFiles = [];
-  renderReplyAttachments();
-  await openConversation(state.activeId);
+  textarea.value = "";
+  try {
+    await api(`/api/admin/conversations/${state.activeId}/messages`, {
+      method: "POST",
+      body: payload
+    });
+    event.currentTarget.reset();
+    state.replyFiles = [];
+    renderReplyAttachments();
+    await openConversation(state.activeId);
+  } catch (error) {
+    textarea.value = originalMessage;
+    throw error;
+  }
 });
 
 $("#replyForm textarea").addEventListener("keydown", (event) => {
@@ -299,7 +306,7 @@ function renderActive() {
   $("#messages").innerHTML = messages.map((message) => `
     <article class="message ${message.senderType}">
       <div class="by">${escapeHtml(message.senderName || message.senderType)} · ${escapeHtml(message.createdAt)}</div>
-      <p>${escapeHtml(message.body)}</p>
+      ${message.body ? `<p>${escapeHtml(message.body)}</p>` : ""}
       ${renderAttachments(message.attachments)}
     </article>
   `).join("");