Project folders for the agent, Local, the menu under its button

- Settings… lists the folders the agent may work in, with the system's
  folder dialog, remove, max mode and terminal, all through
  'lembas remote … --json' (CLI 1.2.0). Turning the agent on with no
  folder opens it; the title bar says 'agent: no folders' instead of green.
- The content webview's User-Agent carries LLeMbasDesktop/<v> (host=…),
  so the server can show this computer's device as Local.
- The title bar menu pops up at the button (popup_menu_at): Wayland gave
  the pointer-less popup the middle of the window.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ui/app.js

@@ -20,13 +20,53 @@ function render(s) {
   $("version").textContent = s.version
   if (s.server && !$("address").value) $("address").value = s.server
   $("agent-section").hidden = !s.server
-  const [text, cls] = (AGENT[s.agent.state] ?? AGENT.off)(s.agent.detail)
+  const noFolders = s.remote && !(s.remote.enabled && s.remote.roots.length)
+  const [text, cls] =
+    s.agent.state === "running" && noFolders
+      ? ["The agent is connected, but may open no folder yet: add one below.", "is-error"]
+      : (AGENT[s.agent.state] ?? AGENT.off)(s.agent.detail)
   const status = $("agent-status")
   status.textContent = text
   status.className = `status ${cls}`
   $("link").textContent = s.linked ? "Link again" : "Link this computer"
   $("toggle").textContent = s.agent_wanted ? "Stop the agent" : "Start the agent"
   $("toggle").disabled = !s.linked && !s.agent_wanted
+  renderFolders(s)
+}
+
+function renderFolders(s) {
+  const r = s.remote
+  $("folders-section").hidden = !s.server || !s.linked || !r
+  if (!r) return
+  const list = $("folders")
+  list.replaceChildren()
+  if (!r.enabled || !r.roots.length) {
+    const li = document.createElement("li")
+    li.className = "empty"
+    li.textContent = "No folder yet: the agent can open nothing. Add the folder of a project."
+    list.append(li)
+  }
+  for (const dir of r.enabled ? r.roots : []) {
+    const li = document.createElement("li")
+    const path = document.createElement("span")
+    path.className = "path"
+    path.title = dir
+    const inner = document.createElement("bdi")
+    inner.textContent = dir
+    path.append(inner)
+    const remove = document.createElement("button")
+    remove.type = "button"
+    remove.className = "btn"
+    remove.textContent = "Remove"
+    remove.setAttribute("aria-label", `Remove ${dir}`)
+    remove.addEventListener("click", () => invoke("remote_remove", { dir }))
+    li.append(path, remove)
+    list.append(li)
+  }
+  if (r.max_mode) $("max-mode").value = r.max_mode
+  $("terminal").checked = !!r.terminal
+  $("folders-status").className = "status"
+  $("folders-status").textContent = ""
 }
 
 async function refresh() {
@@ -70,5 +110,14 @@ $("open").addEventListener("click", async () => {
   if (s.server) await invoke("set_server", { address: s.server })
 })
 
+$("add-folder").addEventListener("click", () => invoke("remote_add"))
+$("max-mode").addEventListener("change", (e) => invoke("remote_mode", { mode: e.target.value }))
+$("terminal").addEventListener("change", (e) => invoke("remote_terminal", { on: e.target.checked }))
+
+listen("remote-error", (e) => {
+  $("folders-status").className = "status is-error"
+  $("folders-status").textContent = String(e.payload)
+})
 listen("status", (e) => render(e.payload))
 refresh()
+invoke("remote_refresh")