A message beside its open editor stands in the browser too (improvise-1x9h)

The toast hid every status after six seconds, so a refusal the user was
still fixing vanished with its prompt open: su4u's bug on a timer. The
browser now asks the TUI's question. EditorSession moves into
improvise-protocol, ClientState records which editor a status was
written in, and RenderModel::status_stands tells the toast to hold it
until that editor closes.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdfEGXA7aJ6ftMsCc9PJze

web/tests/shell.test.js

@@ -125,6 +125,61 @@ test("a host that clears the status hides the toast without waiting", () => {
   assert.equal(clock.count(), 0, "a cleared message leaves no timer behind");
 });
 
+/// improvise-1x9h: a message that stands beside an open editor is the user's
+/// until the editor closes, not the timer's. Evidence: clients.md.
+test("a standing message outlives the timer and goes with its editor", () => {
+  const clock = fakeClock();
+  const shown = [];
+  let visible = false;
+  const toasts = createToasts({
+    onShow: (t) => {
+      shown.push(t);
+      visible = true;
+    },
+    onHide: () => {
+      visible = false;
+    },
+    ttlMs: 6000,
+    setTimer: clock.setTimer,
+    clearTimer: clock.clearTimer,
+  });
+
+  toasts.offer("Formula error", true);
+  assert.equal(clock.count(), 0, "a standing message arms no timer");
+  clock.fire();
+  assert.equal(visible, true, "the refusal hid while its editor was open");
+  toasts.offer("Formula error", true);
+  assert.deepEqual(shown, ["Formula error"], "a repaint is not a second event");
+
+  toasts.offer("Formula error", false);
+  assert.equal(visible, false, "the refusal outlived its editor");
+  assert.equal(clock.count(), 0, "leaving hides now, not on a timer");
+  toasts.offer("Formula error", true);
+  assert.equal(visible, false, "a message that stopped standing came back");
+});
+
+/// The other direction: a message that does not stand is on the timer exactly
+/// as before (improvise-1x9h).
+test("a message that does not stand keeps its timer", () => {
+  const clock = fakeClock();
+  let visible = false;
+  const toasts = createToasts({
+    onShow: () => {
+      visible = true;
+    },
+    onHide: () => {
+      visible = false;
+    },
+    ttlMs: 6000,
+    setTimer: clock.setTimer,
+    clearTimer: clock.clearTimer,
+  });
+  toasts.offer("Formula added", false);
+  assert.equal(clock.count(), 1);
+  clock.fire();
+  assert.equal(visible, false);
+});
+
 test("an empty status on the first frame shows nothing", () => {
   // The common case: every repaint before any command offers "". A feed that
   // treated the first offer as new would flash an empty toast on load.