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/loading_screen.gd

@@ -0,0 +1,83 @@
+# LoadingScreen (P10) —— 相位驱动的读取遮罩。
+#
+#   var ls := preload("res://ui/loading_screen.gd").new()
+#   add_child(ls)
+#   ls.setup(m2client)          # 接 phase_changed；也可手动 show_for("...") / hide()
+#
+# 只有 PHASE = "loading"（载入地图）才铺全屏遮罩；login / select / game 都隐藏
+# —— select 阶段要露出选人界面，login 阶段登录框自己显示进度。
+extends CanvasLayer
+
+const HINTS := {
+	"loading": "载入地图…",
+}
+
+var client: Node
+var _panel: ColorRect
+var _label: Label
+var _spinner: Label
+var _bar: ProgressBar
+var _spin := 0.0
+
+func setup(m2client: Node = null) -> void:
+	client = m2client
+	layer = 60
+	_build()
+	if client and client.has_signal("phase_changed"):
+		client.phase_changed.connect(_on_phase)
+	if client and client.has_signal("disconnected"):
+		client.disconnected.connect(func(_r): hide_screen())
+
+func _on_phase(phase: String) -> void:
+	if phase.to_lower() == "loading":
+		show_for(String(HINTS.get("loading", "载入中…")))
+	else:
+		hide_screen()   # login / select / game —— 让位给对应界面
+
+func show_for(text: String) -> void:
+	_label.text = text
+	_bar.visible = false
+	_panel.visible = true
+
+func set_progress(frac: float) -> void:
+	_bar.visible = true
+	_bar.value = clampf(frac, 0.0, 1.0) * 100.0
+
+func hide_screen() -> void:
+	_panel.visible = false
+
+func is_showing() -> bool:
+	return _panel.visible
+
+func _process(dt: float) -> void:
+	if _panel.visible:
+		_spin += dt * 4.0
+		_spinner.text = ["◐", "◓", "◑", "◒"][int(_spin) % 4]
+
+func _build() -> void:
+	_panel = ColorRect.new()
+	_panel.color = Color(0.02, 0.03, 0.05, 0.96)
+	_panel.set_anchors_preset(Control.PRESET_FULL_RECT)
+	_panel.visible = false
+	add_child(_panel)
+	var box := VBoxContainer.new()
+	box.set_anchors_preset(Control.PRESET_CENTER)
+	box.position = Vector2(-120, -50)
+	box.custom_minimum_size = Vector2(240, 0)
+	box.alignment = BoxContainer.ALIGNMENT_CENTER
+	box.add_theme_constant_override("separation", 14)
+	_panel.add_child(box)
+	_spinner = Label.new()
+	_spinner.text = "◐"
+	_spinner.add_theme_font_size_override("font_size", 36)
+	_spinner.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	box.add_child(_spinner)
+	_label = Label.new()
+	_label.text = "载入中…"
+	_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	box.add_child(_label)
+	_bar = ProgressBar.new()
+	_bar.custom_minimum_size = Vector2(240, 12)
+	_bar.show_percentage = false
+	_bar.visible = false
+	box.add_child(_bar)