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/main.gd

@@ -105,7 +105,7 @@ func _process(delta: float) -> void:
 		if interaction_list and interaction_list.has_method("update_from_state"):
 			if dialogue_box and dialogue_box.is_dialogue_active():
 				if interaction_list.is_showing():
-					interaction_list._hide()
+					interaction_list.hide_list()
 			else:
 				interaction_list.update_from_state()