continuation: only an ellipsis may widen the keyword match

Deployed check, second round: "привет" after "какой сегодня день" answered
with the date. followUpMerge fills an empty Text from the previous
same-intent turn, so the topic-widening added a minute earlier was reading
an inherited topic on turns that had nothing to do with it.

Decision gains Continued, set only by continuation.go and never by the
router. replySystem widens on that and nothing else, so an inherited Text
is back to being invisible.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TrVSBKe3RFDF4fGYKWYQnX

internal/router/intent.go

@@ -104,4 +104,11 @@ type Decision struct {
 	Confidence float64 // 1.0 for stage-0; classifier cosine similarity for 1+
 	Slots      Slots
 	Clarify    bool // stage 3: below threshold — ask, don't guess
+
+	// Continued — this decision was rebuilt from the previous turn rather
+	// than routed, because the utterance was an ellipsis ("а завтра?").
+	// Handlers use it to know that Slots.Text is the PREVIOUS turn's topic
+	// and not something the current utterance said. Nothing in the router
+	// sets it; the daemon's continuation path does.
+	Continued bool
 }