fix(tui): prevent transcript from stealing focus

tui/src/app.test.ts

@@ -1674,21 +1674,23 @@ describe("NanobotTui layout", () => {
     expect(setup.renderer.getSelection()).toBeNull()
   })
 
-  test("returns text input focus when other TUI content is clicked", async () => {
+  test("keeps text input focus when the focusable transcript is clicked", async () => {
     setup = await createRenderer({ width: 72, height: 20, screenMode: "alternate-screen" })
     const app = mount(setup)
     const ui = app as unknown as {
       composer: TextareaRenderable
-      status: TextRenderable
+      transcript: {
+        root: { x: number; y: number; focused: boolean }
+      }
     }
     app.accept({ event: "delta", chat_id: "chat", text: "clickable answer" })
     app.accept({ event: "stream_end", chat_id: "chat" })
     await setup.flush()
 
-    ui.composer.blur()
-    await setup.mockMouse.click(ui.status.x, ui.status.y)
+    await setup.mockMouse.click(ui.transcript.root.x + 1, ui.transcript.root.y + 1)
 
     expect(ui.composer.focused).toBe(true)
+    expect(ui.transcript.root.focused).toBe(false)
   })
 
   test("animates one stable status line while the agent works", async () => {

tui/src/app.ts

@@ -511,7 +511,13 @@ export class NanobotTui {
       backgroundColor: RGBA.defaultBackground(),
       onMouseDown: (event) => {
         if (event.button !== 0) return
-        if (!this.diffViewer.visible) this.composer.focus()
+        if (!this.diffViewer.visible) {
+          // OpenTUI applies automatic focus after mouse handlers run. Prevent
+          // a focusable transcript ancestor from stealing text focus back
+          // after the composer has been restored here.
+          event.preventDefault()
+          this.composer.focus()
+        }
         // Runtime pickers are transient popovers. A primary click anywhere
         // outside their trigger or body dismisses them; hide() restores the
         // composer focus through the shared visibility callback.