Route UI labels through the string table

Move start menu, settings, pause, Help, HUD, radio, shift review and campaign
labels/templates into content/strings.en.json, including placeholder-validated
dynamic status text. No player-facing hardcoded labels remain outside dynamic
data/debug output. Headless 250/250, docs check OK.

src/game/ui/radio_panel.gd

@@ -68,22 +68,22 @@ func _init() -> void:
 	vbox.add_child(npc_name_label)
 
 	location_edit = LineEdit.new()
-	location_edit.placeholder_text = "Location (e.g. front steps)"
-	location_edit.text = "front entrance"
+	location_edit.placeholder_text = Strings.lookup("ui.radio_location_placeholder")
+	location_edit.text = Strings.lookup("ui.radio_location_default")
 	vbox.add_child(location_edit)
 
 	desc_edit = LineEdit.new()
-	desc_edit.placeholder_text = "Describe the person and behavior"
+	desc_edit.placeholder_text = Strings.lookup("ui.radio_description_placeholder")
 	vbox.add_child(desc_edit)
 
 	weapons_check = CheckBox.new()
-	weapons_check.text = "Weapon seen"
+	weapons_check.text = Strings.lookup("ui.radio_weapon")
 	vbox.add_child(weapons_check)
 
 	var danger_row := HBoxContainer.new()
 	vbox.add_child(danger_row)
 	var danger_label := Label.new()
-	danger_label.text = "Danger level: "
+	danger_label.text = Strings.lookup("ui.radio_danger")
 	danger_row.add_child(danger_label)
 	danger_option = OptionButton.new()
 	for i in 4:
@@ -109,7 +109,7 @@ func _init() -> void:
 	action_button.pressed.connect(_on_action_pressed)
 	buttons.add_child(action_button)
 	var cancel_btn := Button.new()
-	cancel_btn.text = "Cancel"
+	cancel_btn.text = Strings.lookup("ui.radio_cancel")
 	cancel_btn.pressed.connect(func(): cancelled.emit())
 	buttons.add_child(cancel_btn)
 
@@ -134,9 +134,9 @@ func open(controller: Object, emergency: bool, truth: Dictionary) -> void:
 	_paint_backdrop()
 	_truth = truth
 	_npc_id = controller.npc_id if controller else ""
-	npc_name_label.text = "Target: %s" % (controller.profile.display_name if controller else "?")
+	npc_name_label.text = Strings.fmt("ui.radio_target", [controller.profile.display_name if controller else "?"])
 	var title: Label = panel.find_child("RadioTitle", true, false)
-	title.text = "EMERGENCY RADIO" if emergency else "RADIO DISPATCH"
+	title.text = Strings.lookup("ui.radio_title_emergency") if emergency else Strings.lookup("ui.radio_title_assist")
 	weapons_check.button_pressed = truth.get("weapons_seen", false)
 	danger_option.select(truth.get("danger_level", 1))
 	hold_hint.text = Strings.fmt("ui.radio_hold_hint", [HOLD_NEEDED]) if emergency else ""