fix(editor): don't autosave while focus is in a popup over the editor

Opening a popup (intentions, completion) moved focus out of the editor and
autosaved it. The save cleanup could change the text, such as trailing
spaces on another line, so the quick fix the popup listed no longer matched
and the first attempt to apply it failed.

While focus is in a popup the editor is not saved; it is saved when focus
moves on from the popup to anything but the editor.

src/editor/core/controller.test.ts

@@ -21,6 +21,51 @@ afterEach(() => {
 });
 
 describe("EditorController", () => {
+  it("autosaves on blur, but not while focus is in a popup over the editor", async () => {
+    const backend = createMemoryBackend({ "/p/a.c": "int main() {\n    \n}\n" });
+    const save = vi.spyOn(backend, "save");
+    ctrl = new EditorController(backend);
+    ctrl.start();
+    await ctrl.openFile("/p/a.c", { focus: false });
+    const slot = ctrl.activeSlot!;
+    const host = document.createElement("div");
+    const popup = document.createElement("div");
+    popup.setAttribute("data-popup", "");
+    const popupList = document.createElement("button");
+    popup.appendChild(popupList);
+    const elsewhere = document.createElement("button");
+    document.body.append(host, popup, elsewhere);
+    try {
+      const view = slot.mount(host);
+      ctrl.onMounted(slot);
+      const type = () => view.dispatch({ changes: { from: 0, insert: "x" }, userEvent: "input.type" });
+      // Into a popup (⌥↵ intentions): nothing is saved while it is open.
+      view.focus();
+      type();
+      popupList.focus();
+      await new Promise((r) => setTimeout(r, 20));
+      expect(save).not.toHaveBeenCalled();
+      // Back to the editor (popup closed): still nothing.
+      view.focus();
+      await new Promise((r) => setTimeout(r, 20));
+      expect(save).not.toHaveBeenCalled();
+      // From the popup elsewhere: saved then.
+      popupList.focus();
+      await new Promise((r) => setTimeout(r, 20));
+      elsewhere.focus();
+      await vi.waitFor(() => expect(save).toHaveBeenCalledTimes(1));
+      // Straight elsewhere: saved.
+      view.focus();
+      type();
+      elsewhere.focus();
+      await vi.waitFor(() => expect(save).toHaveBeenCalledTimes(2));
+    } finally {
+      host.remove();
+      popup.remove();
+      elsewhere.remove();
+    }
+  });
+
   it("leaves modified Enter to a non-text editor after switching from a focused file", async () => {
     ctrl = new EditorController(createMemoryBackend({ "/p/a.ts": "one\ntwo\n" }));
     ctrl.start();