- Reset _npc_entity_colors/_npc_entity_id/_next_npc_color in _end_player_conversation()
to prevent palette exhaustion across long sessions with many unique NPCs
- Re-enforce contrast floor after passive desaturation (_enforce_contrast after _desaturate)
- Add TestDialogueSpeakerColors suite: palette allocation, entity reuse, reset, fallback
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>