Adv 2.0 D&D Phase 11 D8: mood-banded TwinBee aside

Adds a TwinBee aside on room entry when GM mood sits at the extreme
bands (≤19 hostile, ≥80 effusive). Mid-bands stay silent — the aside is
strictly extra flavor, never replacing core narration. Two new pools
(MoodAsidesHostile, MoodAsidesEffusive) live alongside the existing
TwinBee voice in twinbee_gm_flavor.go. Wired into zoneCmdEnter and
zoneCmdAdvance; the advance path reloads the run so post-combat
nat20/nat1 deltas are reflected before band lookup.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/plugin/dnd_zone_narration.go

@@ -381,6 +381,36 @@ func complimentResponseLine(runID string, roomIdx int) string {
 	return "🎭 **TwinBee:** " + line
 }
 
+// moodAsidePool returns the mood-banded aside pool when the mood sits at
+// an extreme band (hostile or effusive), else nil. Mid-bands (grumpy /
+// neutral / friendly) intentionally surface no aside — flavor stays
+// strictly extra, never replacing the core narration.
+func moodAsidePool(mood int) []string {
+	switch moodBand(mood) {
+	case MoodBandHostile:
+		return flavor.MoodAsidesHostile
+	case MoodBandEffusive:
+		return flavor.MoodAsidesEffusive
+	}
+	return nil
+}
+
+// moodAsideLine renders a deterministic TwinBee aside reflecting the
+// run's mood at the extreme bands. roomIdx is folded so the same room
+// in the same run is stable; cross-room asides vary. Returns "" for
+// mid-band moods.
+func moodAsideLine(mood int, runID string, roomIdx int) string {
+	pool := moodAsidePool(mood)
+	if len(pool) == 0 {
+		return ""
+	}
+	line := pickLineDeterministic(pool, runID, roomIdx^0x6F2D8B14)
+	if line == "" {
+		return ""
+	}
+	return "🎭 **TwinBee:** " + line
+}
+
 // ── Mood event table & application ───────────────────────────────────────────
 
 // GMMoodEvent enumerates the mood-modifier triggers from design doc §3.2.