dialogue: a restart expires the parked question (V-385)

The decision, not a behaviour change: ClarifyStore stays in memory, and she
does not announce the loss either.

The TTL and the attempt count measure a pause in one conversation. A restart
is a gap of unknown length, so a restored question is either dead already or
lying about its age, and the request behind it is one he has likely given up
on. Announcing it would mean storing a marker that outlives the thing it
describes, to say one sentence in the rare window where he speaks within 90s
of a restart. His next words route fresh, which is right either way.

Written down in docs/design.md, pinned at both ends by a comment, and held by
a test that builds a second handler over the same store.

docs/design.md

@@ -223,6 +223,30 @@ Not alternatives — layers:
 Router contract: `[{"intent":<enum>, key?, value?, text?, verb?}, ...]` over
 7 intents (`fact, reminder, note, query, act, chat, system`).
 
+#### A restart expires a parked question
+
+Decided 2026-08-04 (Vikunja #385). The follow-up dialogue session survives a
+restart; the clarify question parked behind it does not, and neither do the
+three yes/no confirms in `voice.go`. `ClarifyStore` stays in memory.
+
+Three reasons, in the order they settle it:
+
+- The clock stops meaning anything. A parked question carries a 90s TTL and an
+  attempt count. A restart is a gap of unknown length, so a restored question is
+  either already dead or pretending to be young.
+- Restoring the question restores the request behind it. He asked for something,
+  she asked back, and then the daemon went away. Acting on that minutes later,
+  against words he has probably given up on, is the misroute the stage 3 gate
+  exists to avoid.
+- She does not announce it either. The expiry notice needs to know a question
+  was parked, and knowing that across a restart means storing it. One sentence,
+  in the rare window where he speaks within 90s of a restart, does not pay for a
+  marker that outlives the thing it describes. His next words route fresh, which
+  is the correct answer with or without the notice.
+
+So the notice stays what it is: the in-process TTL case, where she really did
+wait and really did let go.
+
 ### save-where — the two-memory routing axis
 
 One discriminator: **does the loop evaluate a predicate against it?**