feat(user-interaction): declare a plan-review presentation intent on questions

A question may now carry `intent`, a tagged declaration that it IS a decision
of a known shape, so a UI that recognises the tag can present it as such
instead of as a generic option list. The one member is
`{ kind: 'plan-review', approve }`, which plan-mode sets on the exit_plan_mode
review.

An intent shapes presentation only: a UI honouring it answers with the same
option labels a generic UI would send, so the tool reads one answer shape
either way, and a UI that does not know the tag renders the generic flow.
`approve` names the affirmative option rather than relying on option order;
since no type can tie that label to the question's own option list, `ask()`
rejects a mismatch as BAD_INTENT, and the wire schema rejects an unknown tag
outright rather than silently rendering generic.

plan-mode also stops reporting a dismissed review as "the user cancelled
ask_user_question" — a tool it never called. A dismissal now tells the model
the user took the turn back to speak, and to stay in plan mode and wait; every
other ask failure keeps its own message.

packages/ui/user-interaction/tests/user-interaction.spec.ts

@@ -83,4 +83,45 @@ describe('UserInteractionService', () => {
       .rejects.toMatchObject({ name: 'UserInteractionError', code: 'EMPTY_QUESTIONS' })
     expect(p.ask).not.toHaveBeenCalled()
   })
+
+  it('rejects an intent whose approve label names none of its own options', async () => {
+    const ctx = new Context()
+    await ctx.plugin(UserInteractionService)
+    const p = { ask: vi.fn(async () => ({ answers: [] })) }
+    ctx.userInteraction.registerProvider(p)
+    const question = { id: 'plan-review', question: 'Approve?', detail: '# Plan' }
+
+    // A wrong label among offered options, and no options offered at all.
+    for (const options of [[{ label: 'Approve' }], undefined]) {
+      await expect(ctx.userInteraction.ask({
+        questions: [{
+          ...question,
+          ...(options === undefined ? {} : { options }),
+          intent: { kind: 'plan-review', approve: 'Ship it' },
+        }],
+      })).rejects.toMatchObject({ name: 'UserInteractionError', code: 'BAD_INTENT' })
+    }
+    expect(p.ask).not.toHaveBeenCalled()
+  })
+
+  it('passes an intent through once its approve label names an offered option', async () => {
+    const ctx = new Context()
+    await ctx.plugin(UserInteractionService)
+    const p = provider('Approve')
+    ctx.userInteraction.registerProvider(p)
+    const intent = { kind: 'plan-review', approve: 'Approve' } as const
+
+    const result = await ctx.userInteraction.ask({
+      questions: [
+        { id: 'plain', question: 'Proceed?' },
+        {
+          id: 'plan-review', question: 'Approve?', detail: '# Plan',
+          options: [{ label: 'Approve' }, { label: 'Keep planning' }], intent,
+        },
+      ],
+    })
+
+    expect(result.answers).toEqual([{ id: 'plain', selected: ['Approve'] }])
+    expect(p.seen[0]?.questions[1]?.intent).toEqual(intent)
+  })
 })