Metin2 game client (P0–P11) + mobile asset pipeline

Networked client on the existing Godot 4.7 + libgr2 renderer:
- net: m2dev wire protocol (libsodium KX + XChaCha20), auth/select/game
  phases, EntityStore world model, ~all GC/CG headers. char create/delete,
  private shop / mall / cube, SHOP_GC_START_EX, guild, party (+ CG_PARTY_SET_STATE),
  quests, dragon soul, refine, safebox, exchange.
- UI: in-game windows migrated 1:1 from the reference uiscript/root .py —
  char status (/stat), inventory+equipment, select-item ([SELECT_ITEM] quest
  token), system-option + game-option + ESC system menu, private-shop 39-grid,
  party info board, shop tabs, atlas, minimap, quickbar, chat, …
- EterGrnLib polish: GR2 material blend/two-sided, LOD crossfade, motion-event
  dispatch, contact shadow, ray-AABB picking, weapon grip pre-transform.

Portable asset IO (A1) — all extension/libgr2/formats/mtproto reads routed
through godot::FileAccess (res:// PCK works on iOS/Android); standalone-lib
*_path() kept for the non-Godot CTests. AssetResolver + PropertyRegistry
switched to a baked index (bake_asset_index.gd) instead of std::filesystem.

Mobile builds: build-{android,ios}.sh, export-android.sh, pack-assets.sh,
gen-debug-keystore.sh. Assets ship as a zip mounted at runtime by
project/asset_pack.gd (adb push now; HTTP download is a drop-in later).

ctest 10/10, 34 GDScript suites, macOS/iOS/Android all build.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013EJxkHiNKS4kybHS3XKyAJ

project/app_lifecycle.gd

@@ -0,0 +1,85 @@
+# AppLifecycle (F5) —— 移动端应用生命周期集中处理。
+#
+# 把 SceneTree 转发来的 MainLoop 通知收成信号，并做默认动作：后台时暂停游戏
+# 逻辑 / 降帧 / 停 BGM，恢复时还原；iOS 内存告警时广播让各缓存自清。渲染上下文
+# 丢失（Android Vulkan surface）由 Godot 自己重建，我们持有的 GPU 资源都由
+# RenderingServer 托管，无需干预。
+#
+# 用法：
+#   var life := preload("res://app_lifecycle.gd").new()
+#   add_child(life)                       # 越早越好（autoload 亦可）
+#   life.bind(m2client, audio)            # 可选：自动接常见消费方
+#   life.paused.connect(_on_bg); life.resumed.connect(_on_fg)
+extends Node
+
+signal paused                      # 进入后台（NOTIFICATION_APPLICATION_PAUSED）
+signal resumed                     # 回到前台
+signal focus_changed(focused: bool)
+signal memory_warning             # iOS 内存压力
+signal back_requested             # Android 返回键
+signal close_requested            # 窗口关闭请求（桌面）
+
+## 后台时是否 get_tree().paused = true（默认开；纯观战/录像可关）
+var pause_tree_on_background := true
+## 后台时把 max_fps 压到这个值省电（0 = 不改）
+var background_max_fps := 8
+
+var _bound_client: Node
+var _bound_audio: Node
+var _saved_max_fps := 0
+var _bg := false
+
+func _ready() -> void:
+	# 通知在暂停树时也要能收到
+	process_mode = Node.PROCESS_MODE_ALWAYS
+
+func bind(m2client: Node = null, audio: Node = null) -> void:
+	_bound_client = m2client
+	_bound_audio = audio
+
+func is_backgrounded() -> bool:
+	return _bg
+
+func _notification(what: int) -> void:
+	match what:
+		NOTIFICATION_APPLICATION_PAUSED:
+			_enter_background()
+		NOTIFICATION_APPLICATION_RESUMED:
+			_exit_background()
+		NOTIFICATION_APPLICATION_FOCUS_IN, NOTIFICATION_WM_WINDOW_FOCUS_IN:
+			focus_changed.emit(true)
+		NOTIFICATION_APPLICATION_FOCUS_OUT, NOTIFICATION_WM_WINDOW_FOCUS_OUT:
+			focus_changed.emit(false)
+		NOTIFICATION_OS_MEMORY_WARNING:
+			memory_warning.emit()
+		NOTIFICATION_WM_GO_BACK_REQUEST:
+			back_requested.emit()
+		NOTIFICATION_WM_CLOSE_REQUEST:
+			close_requested.emit()
+
+func _enter_background() -> void:
+	if _bg:
+		return
+	_bg = true
+	if background_max_fps > 0:
+		_saved_max_fps = Engine.max_fps
+		Engine.max_fps = background_max_fps
+	if _bound_audio and _bound_audio.has_method("stop_bgm"):
+		_bound_audio.stop_bgm()
+	if _bound_client and _bound_client.has_method("suspend"):
+		_bound_client.suspend()
+	if pause_tree_on_background:
+		get_tree().paused = true
+	paused.emit()
+
+func _exit_background() -> void:
+	if not _bg:
+		return
+	_bg = false
+	if pause_tree_on_background:
+		get_tree().paused = false
+	if background_max_fps > 0:
+		Engine.max_fps = _saved_max_fps
+	if _bound_client and _bound_client.has_method("resume"):
+		_bound_client.resume()
+	resumed.emit()