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/pause_overlay.gd

@@ -10,6 +10,7 @@ signal settings_requested()
 signal quit_to_menu_requested()
 
 const UiArt := preload("res://src/game/ui/art.gd")
+const Strings := preload("res://src/core/strings.gd")
 
 var _root: Control = null
 var _resume_button: Button = null
@@ -45,18 +46,18 @@ func _build() -> void:
 	center.add_child(column)
 
 	var title := Label.new()
-	title.text = "Paused"
+	title.text = Strings.lookup("ui.pause_title")
 	title.add_theme_font_size_override("font_size", 36)
 	title.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
 	column.add_child(title)
 
-	_resume_button = _add_button(column, "Resume", "ResumeButton", func(): resume_requested.emit())
-	_add_button(column, "Restart shift", "RestartButton", func(): restart_requested.emit())
-	_add_button(column, "Settings", "SettingsButton", func(): settings_requested.emit())
-	_add_button(column, "Quit to menu", "MenuButton", func(): quit_to_menu_requested.emit())
+	_resume_button = _add_button(column, Strings.lookup("ui.pause_resume"), "ResumeButton", func(): resume_requested.emit())
+	_add_button(column, Strings.lookup("ui.pause_restart"), "RestartButton", func(): restart_requested.emit())
+	_add_button(column, Strings.lookup("ui.pause_settings"), "SettingsButton", func(): settings_requested.emit())
+	_add_button(column, Strings.lookup("ui.pause_menu"), "MenuButton", func(): quit_to_menu_requested.emit())
 
 	var hint := Label.new()
-	hint.text = "Esc resumes"
+	hint.text = Strings.lookup("ui.pause_hint")
 	hint.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
 	hint.add_theme_color_override("font_color", Color(0.55, 0.58, 0.65))
 	column.add_child(hint)