fix(client): address PR review warnings — field guard + public API rename

- main.gd: add has("entity_id") guard to _play_recognition_chimes()
  (matches defensive pattern in _play_close_sound_events and update_sound_events)
- sound_indicator_renderer.gd: rename _color_for_type → color_for_type
  (public testable API, not an internal-only method)
- test_rendering.gd: update test calls to match rename

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/scripts/rendering/sound_indicator_renderer.gd

@@ -111,7 +111,7 @@ func _draw() -> void:
 		else:
 			alpha = lerpf(1.0, 0.0, (t - fade_start) / (FADE_DURATION / INDICATOR_LIFETIME))
 
-		var color: Color = _color_for_type(ind.event_type)
+		var color: Color = color_for_type(ind.event_type)
 		color.a = alpha * 0.9
 		_draw_arrow(edge_pt, dir, color)
 
@@ -142,7 +142,7 @@ func _draw_arrow(pos: Vector2, dir: Vector2, color: Color) -> void:
 
 
 ## Map event type string → D-018 color category.
-func _color_for_type(event_type: String) -> Color:
+func color_for_type(event_type: String) -> Color:
 	var et := event_type.to_lower()
 	if et.contains("voice") or et.contains("speech") or et.contains("convers") or et.contains("talk"):
 		return COLOR_VOICE