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/plan/plan-mode/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/plan/plan-mode/README.md
-README.md: d3c2c14fe616e1c9b4e33b716570b084db6474cf
-README.zh.md: 6d6878c4b0300a716ad16be60fd86bc79f1514ba
+README.md: 6f0a9ac477b49b96ddfc2ce667e3556dec727569
+README.zh.md: 922b153aa1b08e1a6003f63736ea402787bff1dd