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/char_shadow.gd

@@ -0,0 +1,43 @@
+# CharShadow —— 角色脚下阴影(첫 버전).
+#
+# 参考端 `GameLib/MapOutdoorCharacterShadow.cpp` 把角色渲到小 RT + 投一张模糊暗贴图
+# 到脚下。这里按「结果」对齐,不复刻 RT:
+#   1) 强制角色所有 MeshInstance3D `cast_shadow = ON`(挡住 world 里 OFF 的误伤)
+#   2) 脚下一张径向渐变 `Decal`,投影到地形/物体上 —— 太阳接近正午投影很短时也有接触暗影
+#
+#   CharShadow.attach(entity_root_node3d)   # 传实体根(不是内部 make_conv 的 Metin2Model)
+extends RefCounted
+class_name CharShadow
+
+static var _tex: Texture2D
+
+static func _blob_tex() -> Texture2D:
+	if _tex != null:
+		return _tex
+	var sz := 64
+	var img := Image.create_empty(sz, sz, false, Image.FORMAT_RGBA8)
+	var c := sz * 0.5
+	for y in sz:
+		for x in sz:
+			var d := Vector2(x + 0.5 - c, y + 0.5 - c).length() / c
+			var a: float = clampf(1.0 - d, 0.0, 1.0)
+			img.set_pixel(x, y, Color(0.0, 0.0, 0.0, a * a * 0.55))
+	_tex = ImageTexture.create_from_image(img)
+	return _tex
+
+static func attach(root: Node3D, footprint := 1.4) -> void:
+	if root == null:
+		return
+	for m in root.find_children("*", "MeshInstance3D", true, false):
+		(m as MeshInstance3D).cast_shadow = GeometryInstance3D.SHADOW_CASTING_SETTING_ON
+	if root.has_node("BlobShadow"):
+		return
+	var dec := Decal.new()
+	dec.name = "BlobShadow"
+	dec.texture_albedo = _blob_tex()
+	# size = 投影盒 (x,z 足印;y 向下够到地面即可)
+	dec.size = Vector3(footprint, 2.5, footprint)
+	dec.modulate = Color(1, 1, 1, 0.55)
+	dec.position = Vector3(0, 0.6, 0)   # 盒中心略高于脚,向下投
+	dec.cull_mask = 0xFFFFF
+	root.add_child(dec)