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/ui/system_menu_ui.gd

@@ -0,0 +1,122 @@
+# SystemMenuUI (P11) —— ESC 系统菜单（1:1 迁移 `assets/root/uisystem.py` `SystemDialog`
+# 的 `__LoadSystemMenu_Default`；布局走真 `assets/uiscript/uiscript/systemdialog.py`）。
+#
+#   var sm := preload("res://ui/system_menu_ui.gd").new()
+#   add_child(sm)
+#   sm.setup(ui_manager, m2client, assets_root, system_option_ui, game_option_ui)
+#   sm.toggle()      # ESC（无其它窗打开时）
+#
+# 按钮绑定逐字对照 uisystem.py：
+#   help_button          → OpenHelpWindow（暂无帮助窗 → 提示）
+#   mall_button          → net.SendChatPacket("/in_game_mall")
+#   system_option_button → uiSystemOption.OptionDialog（system_option_ui）
+#   game_option_button   → uiGameOption.OptionDialog（game_option_ui）
+#   change_button        → net.ExitGame() = SendChatPacket("/phase_select")
+#   logout_button        → net.LogOutGame() = SendChatPacket("/logout")
+#   exit_button          → net.ExitApplication() = 退出进程
+#   cancel_button / 标题栏 → 关闭
+extends Node
+
+const LABELS := {
+	"help_button": "帮助", "mall_button": "商城", "system_option_button": "系统设置",
+	"game_option_button": "游戏设置", "change_button": "选择角色", "logout_button": "登出",
+	"exit_button": "退出游戏", "cancel_button": "取消",
+}
+
+var ui: CanvasLayer
+var client: Node
+var assets_root := ""
+var uiscript_dir := ""
+var system_option_ui: Node
+var game_option_ui: Node
+var toast: Callable = Callable()   # 可选：func(msg: String) 显示提示
+
+var _win: Dictionary = {}
+
+func setup(ui_manager: CanvasLayer, m2client: Node, assets := "",
+		sys_opt: Node = null, game_opt: Node = null) -> void:
+	ui = ui_manager
+	client = m2client
+	system_option_ui = sys_opt
+	game_option_ui = game_opt
+	assets_root = assets
+	if assets_root == "" and ui and "assets_root" in ui:
+		assets_root = ui.assets_root
+	uiscript_dir = assets_root.path_join("uiscript/uiscript")
+	if not DirAccess.dir_exists_absolute(uiscript_dir):
+		uiscript_dir = assets_root.path_join("uiscript")
+
+func is_open() -> bool:
+	return not _win.is_empty() and is_instance_valid(_win.get("root"))
+
+func toggle() -> void:
+	if is_open(): close()
+	else: open()
+
+func close() -> void:
+	if is_open():
+		ui.close(_win["root"])
+	_win = {}
+
+func open() -> void:
+	if is_open():
+		return
+	var path := uiscript_dir.path_join("systemdialog.py")
+	if not FileAccess.file_exists(path):
+		push_warning("SystemMenuUI: no systemdialog.py at " + path)
+		return
+	_win = ui.open_script(path, assets_root, true)   # modal
+	if not is_open():
+		return
+	_relabel()
+	_wire()
+
+func _node(nm: String) -> Control:
+	if _win.is_empty():
+		return null
+	var n = _win.get("nodes", {}).get(nm, null)
+	return n if n is Control else null
+
+func _relabel() -> void:
+	for nm in LABELS:
+		var n := _node(nm)
+		if n and n.has_method("set_text"):
+			n.set_text(LABELS[nm])
+
+func _btn(nm: String, cb: Callable) -> void:
+	var b := _node(nm)
+	if b is BaseButton:
+		b.pressed.connect(cb)
+
+func _wire() -> void:
+	_btn("help_button", func():
+		if toast.is_valid():
+			toast.call("帮助窗暂未实现")
+		)
+	_btn("mall_button", func():
+		if client and client.has_method("say"):
+			client.say(0, "/in_game_mall")   # net.SendChatPacket("/in_game_mall")
+		close())
+	_btn("system_option_button", func():
+		close()
+		if system_option_ui and system_option_ui.has_method("open"):
+			system_option_ui.open())
+	_btn("game_option_button", func():
+		close()
+		if game_option_ui and game_option_ui.has_method("open"):
+			game_option_ui.open())
+	_btn("change_button", func():
+		if client and client.has_method("say"):
+			client.say(0, "/phase_select")   # net.ExitGame()
+		close())
+	_btn("logout_button", func():
+		if client and client.has_method("say"):
+			client.say(0, "/logout")         # net.LogOutGame()
+		close())
+	_btn("exit_button", func(): get_tree().quit())
+	_btn("cancel_button", close)
+	var board := _node("board")
+	if board:
+		for x in board.find_children("*", "BaseButton", true, false):
+			if x.get_meta("is_titlebar", false):
+				x.pressed.connect(close)