Approval cards show again: the buttons no longer throw, the command is the item's detail

An agent chat's bash approval left "Waiting for you to allow bash…" with no card: cardOf()
called append(actions, a, b, c) while append() took one array, so `children.flat` threw for
every approval and plan card (questions used el.append and worked). renderCards() had already
unhidden #cards, which stayed empty. append() now takes children as rest arguments too.

- The editable command is `detail` (services/device_link.py puts the fixed "Run a command" in
  the title); it is sent back as the item's text only when changed. Non-editable approvals
  show the title and the device's input. `purpose` ("It says: …"), `reason` and the asking
  subagent (`job`) are shown, as on the web page.
- renderCards() keeps a card already on the screen (by id) instead of drawing every card again
  on each `ask` frame, which the server re-sends whenever the countdown changes; a card that
  cannot be drawn shows the error instead of an empty box.
- tests/ui/: headless harness with a mocked Tauri bridge; five A1 cases (device bash card
  shows and is visible, Allow/edit/Deny post to /chats/{id}/interactions/{card}, redraw keeps
  edits, reopen gets the card from the stream's first pass, 390 px).

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

tests/ui/mock-tauri.js

@@ -0,0 +1,100 @@
+// A stand-in for Tauri's bridge, for the page under a headless browser (tests/ui/run.mjs). Runs
+// before the page's own scripts: `window.__TAURI__` answers the commands the page invokes from a
+// table the test hands in, and records every call, so a test can say what the page asked for.
+//
+// The table (`config`):
+//   status   what `get_status` answers (the app, the agent, the server)
+//   routes   { "GET /me": value, "POST /chats/c1/interactions/k1": value, ... } -- the server's
+//            /api/v2 as the page reaches it through `api`. A path is looked up with its query,
+//            then without it. A value `{ __error: { status, detail } }` is a refusal. Anything
+//            not in the table is a 404, as an older server would answer.
+//   streams  { "/chats/c1/messages/m1/stream": [[event, data], ...] } -- the frames a followed
+//            reply sends as soon as it is opened. More can be sent later with `__mock.frame()`.
+//
+// Nothing here talks to a network: the page's policy allows it none, and this keeps it so.
+;(function () {
+  const config = window.__mockConfig || {}
+  const listeners = new Map() // event name -> [callback]
+  const streams = new Map() // stream id -> path
+  let nextStream = 0
+  const calls = []
+
+  function dispatch(name, payload) {
+    for (const cb of listeners.get(name) || []) cb({ event: name, payload })
+  }
+
+  function route(method, path) {
+    const routes = config.routes || {}
+    const bare = path.split("?")[0]
+    for (const key of [`${method} ${path}`, `${method} ${bare}`]) {
+      if (Object.prototype.hasOwnProperty.call(routes, key)) {
+        const value = routes[key]
+        if (value && value.__error) return Promise.reject(value.__error)
+        return Promise.resolve(JSON.parse(JSON.stringify(value)))
+      }
+    }
+    return Promise.reject({ status: 404, detail: `Not in the test's table: ${method} ${path}` })
+  }
+
+  function frame(path, event, data) {
+    for (const [id, p] of streams) if (p === path) dispatch("stream", { id, event, data })
+  }
+
+  async function invoke(cmd, args) {
+    calls.push({ cmd, args: args === undefined ? null : JSON.parse(JSON.stringify(args)) })
+    switch (cmd) {
+      case "get_status":
+        return JSON.parse(JSON.stringify(config.status))
+      case "api":
+        return route(args.method, args.path)
+      case "api_text":
+        return route("GET", args.path)
+      case "stream_open": {
+        const id = ++nextStream
+        streams.set(id, args.path)
+        const frames = (config.streams || {})[args.path] || []
+        setTimeout(() => {
+          for (const [event, data] of frames) dispatch("stream", { id, event, data })
+        }, 0)
+        return id
+      }
+      case "stream_close":
+        streams.delete(args.id)
+        return null
+      case "model_image":
+        return ""
+      case "terminal_word":
+        return "lembas"
+      default:
+        return null
+    }
+  }
+
+  const win = {
+    minimize: async () => {},
+    toggleMaximize: async () => {},
+    close: async () => {},
+    isMaximized: async () => false,
+  }
+
+  window.__TAURI__ = {
+    core: { invoke },
+    event: {
+      listen: async (name, cb) => {
+        if (!listeners.has(name)) listeners.set(name, [])
+        listeners.get(name).push(cb)
+        return () => listeners.set(name, (listeners.get(name) || []).filter((x) => x !== cb))
+      },
+    },
+    window: { getCurrentWindow: () => win },
+  }
+
+  window.__mock = {
+    calls,
+    frame,
+    emit: dispatch,
+    /** The calls of one command, or of `api` with one method and path prefix. */
+    api: (method, prefix) => calls.filter((c) => c.cmd === "api" && c.args.method === method && c.args.path.startsWith(prefix)),
+    streams: () => [...streams.values()],
+  }
+})()