add a major part of user level

app/public/guild/goodbyeForm.js

@@ -0,0 +1,32 @@
+const goodbyeForm = document.getElementById("goodbye-form");
+const goodbyeEnabled = document.getElementById("goodbye-enabled");
+const goodbyeChannel = document.getElementById("goodbye-channel");
+const goodbyeMessage = document.getElementById("goodbye-message");
+const statusGoodbyeForm = document.getElementById("status-goodbye-form");
+
+fetch(`/api/bot/get-goodbye-config/${guildId}`)
+  .then(res => res.json())
+  .then(cfg => {
+    goodbyeEnabled.checked = cfg.enabled;
+    goodbyeChannel.value = cfg.channelId;
+    goodbyeMessage.value = cfg.message;
+  });
+
+goodbyeForm.addEventListener("submit", async e => {
+  e.preventDefault();
+
+  const res = await fetch("/api/bot/save-goodbye-config", {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({
+      guildId,
+      goodbyeEnabled: goodbyeEnabled.checked,
+      channelId: goodbyeChannel.value,
+      goodbyeMessage: goodbyeMessage.value
+    })
+  });
+
+  statusGoodbyeForm.textContent = (await res.json()).success
+    ? "Config au revoir sauvegardée ✅"
+    : "Erreur ❌";
+});