Feature-gate Dynamic Questions and CCS Cases to UAT only

Both are still in progress and shouldn't be reachable in production
(or local dev) yet - hide every entry point (nav sidebar, the
dashboard's "dynamic concepts due" review card, and the CCS Cases
mode card on the study selector) unless step3/deployment_environment
is "uat", the same setting that already drives the UAT badge. Added
Brand.is_uat_environment() as the shared check.

scripts/ui/study_selector.gd

@@ -187,18 +187,19 @@ func _build_mode_view() -> void:
 	retry_button = question_card.retry
 	retry_button.pressed.connect(_retry_question_bank)
 
-	var ccs_card := _add_mode_card(
-		"CCS Cases",
-		"Interactive case simulations",
-		"Available",
-		"Available",
-		"Practice real-world clinical scenarios and\nimprove your management skills.",
-		"stethoscope",
-		true,
-		Brand.TEAL)
-	ccs_button = ccs_card.action
-	ccs_status_label = ccs_card.status
-	ccs_button.pressed.connect(_select_ccs)
+	if Brand.is_uat_environment():
+		var ccs_card := _add_mode_card(
+			"CCS Cases",
+			"Interactive case simulations",
+			"Available",
+			"Available",
+			"Practice real-world clinical scenarios and\nimprove your management skills.",
+			"stethoscope",
+			true,
+			Brand.TEAL)
+		ccs_button = ccs_card.action
+		ccs_status_label = ccs_card.status
+		ccs_button.pressed.connect(_select_ccs)
 
 
 func _build_question_bank_launch_view() -> void: