fix(client): address PR #62 review — input guard, public API, geometry cache

- constants.gd: clamp format_game_time input to 0..1439 (Hoshe #2)
- interaction_list.gd: add public hide_list() wrapper (Hoshe #3, Tyre #1)
- main.gd: call hide_list() instead of private _hide()
- time_display.gd: cache font geometry in update_from_state(), use boolean
  _has_data flag instead of string guard (Tyre #2)

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

client/scripts/constants.gd

@@ -98,9 +98,8 @@ const DIALOGUE_MAX_WIDTH: int = 1200
 
 # D-031: Format game-minutes (0..1439) as station local time string "HH:MM".
 static func format_game_time(time_of_day: int) -> String:
-	var hours: int = time_of_day / 60
-	var minutes: int = time_of_day % 60
-	return "%02d:%02d" % [hours, minutes]
+	var clamped: int = clampi(time_of_day, 0, 1439)
+	return "%02d:%02d" % [clamped / 60, clamped % 60]
 
 # Default camera zoom — used as fallback when get_camera_2d() returns null
 const CAMERA_DEFAULT_ZOOM: Vector2 = Vector2(2.0, 2.0)