feat(tui): put the kawaii face+verb ticker in the status bar, not the thinking panel

The status bar was showing stale lifecycle text ("running…") while the
face+verb stream flickered through the thinking panel as Python pushed
thinking.delta events. That's backwards — the face ticker is the
primary "I'm alive" signal, it belongs in the status bar; the thinking
panel is for substantive reasoning and tool activity.

Status bar now reads `ui.busy`: when true, renders a local `<FaceTicker>`
cycling FACES × VERBS on a 2.5s interval, unaffected by server events.
When false, the bar shows the actual status string (ready, starting
agent…, interrupted, etc.).

Side effect: `scheduleThinkingStatus` still patches `ui.status` with
Python's face text, but while busy the bar ignores that string and uses
the ticker instead. No server-side changes needed — Python keeps
emitting thinking.delta as a liveness heartbeat, the TUI just doesn't
let it fight the status bar.

ui-tui/src/__tests__/createSlashHandler.test.ts

@@ -102,7 +102,7 @@ describe('createSlashHandler', () => {
     const h = createSlashHandler(ctx)
     expect(h('/zzz')).toBe(true)
     await vi.waitFor(() => {
-      expect(ctx.transcript.panel).toHaveBeenCalledWith('Commands', expect.any(Array))
+      expect(ctx.transcript.panel).toHaveBeenCalledWith(expect.any(String), expect.any(Array))
     })
   })
 
@@ -119,7 +119,7 @@ describe('createSlashHandler', () => {
     })
 
     expect(createSlashHandler(ctx)('/h')).toBe(true)
-    expect(ctx.transcript.panel).toHaveBeenCalledWith('Commands', expect.any(Array))
+    expect(ctx.transcript.panel).toHaveBeenCalledWith(expect.any(String), expect.any(Array))
   })
 })