fix(tui): keep todo pinned outside transcript

ui-tui/src/lib/liveLayout.test.ts

@@ -4,6 +4,6 @@ import { liveTailOrder } from './liveLayout.js'
 
 describe('liveTailOrder', () => {
   it('keeps todo before transcript and assistant live output', () => {
-    expect(liveTailOrder()).toEqual(['todo', 'history', 'assistant'])
+    expect(liveTailOrder()).toEqual(['todo', 'scroll-history', 'assistant'])
   })
 })

ui-tui/src/lib/liveLayout.ts

@@ -1 +1 @@
-export const liveTailOrder = () => ['todo', 'history', 'assistant'] as const
+export const liveTailOrder = () => ['todo', 'scroll-history', 'assistant'] as const

ui-tui/src/lib/messages.test.ts

@@ -0,0 +1,23 @@
+import { describe, expect, it } from 'vitest'
+
+import { appendTranscriptMessage } from './messages.js'
+
+describe('appendTranscriptMessage', () => {
+  it('merges adjacent tool-only shelves into one transcript row', () => {
+    const out = appendTranscriptMessage(
+      [{ kind: 'trail', role: 'system', text: '', tools: ['Terminal("one") ✓'] }],
+      { kind: 'trail', role: 'system', text: '', tools: ['Terminal("two") ✓'] }
+    )
+
+    expect(out).toEqual([{ kind: 'trail', role: 'system', text: '', tools: ['Terminal("one") ✓', 'Terminal("two") ✓'] }])
+  })
+
+  it('does not merge tool shelves across thinking text', () => {
+    const out = appendTranscriptMessage(
+      [{ kind: 'trail', role: 'system', text: '', thinking: 'plan', tools: ['Terminal("one") ✓'] }],
+      { kind: 'trail', role: 'system', text: '', tools: ['Terminal("two") ✓'] }
+    )
+
+    expect(out).toHaveLength(2)
+  })
+})

ui-tui/src/lib/messages.ts

@@ -1,4 +1,17 @@
 import type { Msg, Role } from '../types.js'
 
+const isToolShelf = (msg: Msg | undefined) =>
+  Boolean(msg?.kind === 'trail' && !msg.text && !msg.thinking?.trim() && msg.tools?.length)
+
+export const appendTranscriptMessage = (prev: Msg[], msg: Msg): Msg[] => {
+  if (isToolShelf(msg) && isToolShelf(prev.at(-1))) {
+    const last = prev.at(-1)!
+
+    return [...prev.slice(0, -1), { ...last, tools: [...(last.tools ?? []), ...(msg.tools ?? [])] }]
+  }
+
+  return [...prev, msg]
+}
+
 export const upsert = (prev: Msg[], role: Role, text: string): Msg[] =>
   prev.at(-1)?.role === role ? [...prev.slice(0, -1), { role, text }] : [...prev, { role, text }]