Reduce answer review scroll redraws

scripts/ui/question_player.gd

@@ -60,6 +60,8 @@ var stem_plain_text := ""
 var explanation_plain_text := ""
 var highlight_drag_source := ""
 var timer_color_state := ""
+var last_timer_bar_value := -1.0
+var last_timer_display_seconds := -1
 var pending_correct_advance := false
 var question_text_scale := 1.0
 var presented_choices: Array = []
@@ -1268,6 +1270,8 @@ func _load_question() -> void:
 	flagged = false
 	selected_choice = ""
 	current_answer = {}
+	last_timer_bar_value = -1.0
+	last_timer_display_seconds = -1
 	flag_button.button_pressed = false
 	_refresh_toolbar_state()
 	_clear_answer_review()
@@ -2094,7 +2098,10 @@ func _update_timer_bar() -> void:
 		return
 	var is_core_timer := BlockSessionService.session_kind == "core"
 	var ratio := BlockSessionService.get_session_timer_ratio()
-	timer_bar.value = ratio * 100.0
+	var next_value := ratio * 100.0
+	if last_timer_bar_value < 0.0 or absf(next_value - last_timer_bar_value) >= 0.1:
+		last_timer_bar_value = next_value
+		timer_bar.value = next_value
 	if is_core_timer and timer_label.visible:
 		_set_timer_display(int(floor(BlockSessionService.get_core_question_total_elapsed_seconds())))
 	var color_state := "blue"
@@ -2114,6 +2121,9 @@ func _set_timer_display(total_seconds: int) -> void:
 	if timer_label == null:
 		return
 	var safe_seconds := maxi(0, total_seconds)
+	if safe_seconds == last_timer_display_seconds:
+		return
+	last_timer_display_seconds = safe_seconds
 	timer_label.text = "%02d:%02d" % [int(floor(float(safe_seconds) / 60.0)), safe_seconds % 60]