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.

scripts/type-equiv.manifest.json

@@ -694,6 +694,11 @@
       "symbol": "AskUserQuestionOption",
       "source": "packages/ui/user-interaction/src/types.ts"
     },
+    {
+      "doc": "docs/core-data-structures/user-interaction.md",
+      "symbol": "AskUserQuestionIntent",
+      "source": "packages/ui/user-interaction/src/types.ts"
+    },
     {
       "doc": "docs/core-data-structures/user-interaction.md",
       "symbol": "AskUserQuestionItem",