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/exchange_ui.gd

@@ -0,0 +1,150 @@
+# ExchangeUI (P8) —— 交易 / 换货窗。
+#
+#   var xu := preload("res://ui/exchange_ui.gd").new()
+#   add_child(xu)
+#   xu.setup(m2client, canvas_parent, proto)   # proto 可空
+#
+# 两栏：我方 / 对方，各列道具行 + 金币。底部：金币输入 + [放金币]、[接受]、[取消]。
+# `exchange_changed` 刷新（active=false 时自动关闭）。
+# inventory_ui 在交易开着时右键道具 → 调 xu.offer(win, cell)。
+extends Node
+
+var client: Node
+var proto: Node
+var _root: Control
+var _self_box: VBoxContainer
+var _peer_box: VBoxContainer
+var _self_gold: Label
+var _peer_gold: Label
+var _accept_btn: Button
+var _gold_input: LineEdit
+var _next_display := 0
+
+func setup(m2client: Node, parent: Node, proto_node: Node = null) -> void:
+	client = m2client
+	proto = proto_node
+	_build(parent)
+	if client.has_signal("exchange_changed"):
+		client.exchange_changed.connect(refresh)
+
+func is_open() -> bool:
+	return _root != null and _root.visible
+
+func offer(inv_window: int, inv_cell: int) -> void:
+	if is_open():
+		client.exchange_add_item(inv_window, inv_cell, _next_display)
+		_next_display = (_next_display + 1) % 12
+
+func _name_of(vnum: int) -> String:
+	if proto and proto.has_method("item"):
+		var d: Dictionary = proto.item(vnum)
+		var n := String(d.get("locale_name", d.get("name", "")))
+		if n != "":
+			return n
+	return "#%d" % vnum
+
+func refresh() -> void:
+	if client == null:
+		return
+	var x: Dictionary = client.get_exchange()
+	if not x.get("active", false):
+		_root.visible = false
+		_next_display = 0
+		return
+	_root.visible = true
+	_fill(_self_box, x.get("self_items", []))
+	_fill(_peer_box, x.get("peer_items", []))
+	_self_gold.text = "金币: %d" % int(x.get("self_gold", 0))
+	_peer_gold.text = "金币: %d" % int(x.get("peer_gold", 0))
+	var me: bool = x.get("self_accept", false)
+	var peer: bool = x.get("peer_accept", false)
+	_accept_btn.text = "已接受 ✓" if me else "接受"
+	_accept_btn.modulate = Color(0.5, 1, 0.5) if me else Color(1, 1, 1)
+	_root.get_node("PeerAccept").text = "对方: 已接受" if peer else "对方: 未接受"
+
+func _fill(box: VBoxContainer, rows: Array) -> void:
+	for c in box.get_children():
+		c.queue_free()
+	for r in rows:
+		var l := Label.new()
+		l.text = "%s ×%d" % [_name_of(int(r.get("vnum", 0))), int(r.get("count", 1))]
+		l.add_theme_font_size_override("font_size", 12)
+		box.add_child(l)
+
+func _on_put_gold() -> void:
+	var g := int(_gold_input.text)
+	if g > 0:
+		client.exchange_add_gold(g)
+
+func _build(parent: Node) -> void:
+	_root = Control.new()
+	_root.set_anchors_preset(Control.PRESET_CENTER)
+	_root.position = Vector2(-220, -180)
+	_root.size = Vector2(440, 360)
+	_root.visible = false
+	_root.set_meta("is_titlebar", true)
+	parent.add_child(_root)
+	var panel := Panel.new()
+	panel.set_anchors_preset(Control.PRESET_FULL_RECT)
+	var sb := StyleBoxFlat.new()
+	sb.bg_color = Color(0.07, 0.08, 0.1, 0.97)
+	sb.set_corner_radius_all(4)
+	panel.add_theme_stylebox_override("panel", sb)
+	_root.add_child(panel)
+	var title := Label.new()
+	title.text = "交易"
+	title.position = Vector2(12, 8)
+	_root.add_child(title)
+
+	var sl := Label.new()
+	sl.text = "我方"
+	sl.position = Vector2(20, 34)
+	_root.add_child(sl)
+	_self_box = VBoxContainer.new()
+	_self_box.position = Vector2(20, 56)
+	_self_box.custom_minimum_size = Vector2(200, 0)
+	_root.add_child(_self_box)
+	_self_gold = Label.new()
+	_self_gold.text = "金币: 0"
+	_self_gold.position = Vector2(20, 250)
+	_root.add_child(_self_gold)
+
+	var pl := Label.new()
+	pl.text = "对方"
+	pl.position = Vector2(240, 34)
+	_root.add_child(pl)
+	_peer_box = VBoxContainer.new()
+	_peer_box.position = Vector2(240, 56)
+	_peer_box.custom_minimum_size = Vector2(180, 0)
+	_root.add_child(_peer_box)
+	_peer_gold = Label.new()
+	_peer_gold.text = "金币: 0"
+	_peer_gold.position = Vector2(240, 250)
+	_root.add_child(_peer_gold)
+
+	var pa := Label.new()
+	pa.name = "PeerAccept"
+	pa.text = "对方: 未接受"
+	pa.position = Vector2(240, 272)
+	pa.add_theme_font_size_override("font_size", 12)
+	_root.add_child(pa)
+
+	var bottom := HBoxContainer.new()
+	bottom.position = Vector2(20, 300)
+	_root.add_child(bottom)
+	_gold_input = LineEdit.new()
+	_gold_input.placeholder_text = "金币"
+	_gold_input.custom_minimum_size = Vector2(90, 0)
+	bottom.add_child(_gold_input)
+	var put := Button.new()
+	put.text = "放金币"
+	put.pressed.connect(_on_put_gold)
+	bottom.add_child(put)
+	_accept_btn = Button.new()
+	_accept_btn.text = "接受"
+	_accept_btn.pressed.connect(func() -> void: client.exchange_accept())
+	bottom.add_child(_accept_btn)
+	var cancel := Button.new()
+	cancel.text = "取消"
+	cancel.pressed.connect(func() -> void: client.exchange_cancel())
+	bottom.add_child(cancel)