Entity renderer now tracks relationship per entity and tweens D-033
tint color over 0.7s when relationship changes (e.g. on confrontation
delivery). Uses manual lerp in _process() for testability instead of
SceneTree tweens. Cursor hover tint cascades automatically via
Constants.color_for_entity_kind().
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>