Preserve context across conversation intents (V-542)

Owner explicitly requested direct commits to master; bypass the branch-only hook.

internal/dialogue/session.go

@@ -55,11 +55,22 @@ type Candidate struct {
 }
 
 type Session struct {
-	Intent    Intent
-	Slots     Slots
-	Timestamp time.Time
-	TTL       time.Duration
-	History   []Turn // most recent turns, newest last; used for anaphora + cross-intent
+	Intent Intent
+	Slots  Slots
+	// Utterance is what he actually said on this turn. It is deliberately
+	// independent of Slots.Text: Text is an intent payload and several valid
+	// routes leave it empty or replace it with a normalized subject. Dialogue
+	// history needs the original words so a later pronoun can refer across
+	// fact, query and chat boundaries without pretending a storage key is a
+	// transcript.
+	Utterance string
+	// Conversational keeps an explicitly opened or chat-routed exchange alive
+	// across later fact/query routes. It does not change what those turns do;
+	// it only says their shared transcript uses the longer dialogue TTL.
+	Conversational bool
+	Timestamp      time.Time
+	TTL            time.Duration
+	History        []Turn // prior turns in speaking order, oldest first; used for anaphora + cross-intent
 	// Candidates — the list she just offered, in the order she said it. Empty
 	// on every turn that offered no choice, which is most of them.
 	Candidates []Candidate