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

extension/src/static_object.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include <godot_cpp/classes/array_mesh.hpp>
+#include <godot_cpp/classes/ref.hpp>
+
+#include <map>
+#include <string>
+
+namespace fmt {
+struct AssetResolver;
+}
+
+namespace mtgodot {
+
+// W3 —— 静态（无骨骼）GR2 对象。用 gr2_bridge 的 build_parts/build_mesh，
+// 逐 surface 从 gr2 material binding 取贴图（走 AssetResolver 定位 + dxt 解码），
+// 不建 Skeleton3D、不逐帧蒙皮。Building / DungeonBlock 用。SHINSOO §9-W3。
+//
+// SHINSOO §9-W3「Metin2StaticModel 新节点 vs 拆 Metin2Model」的决策：
+// 取轻量方案 —— 一个自由函数产出带材质的共享 ArrayMesh，调用方（Metin2World）
+// 直接挂到 MeshInstance3D，跨实例共享同一份 mesh。
+struct StaticMeshCache {
+	std::map<std::string, godot::Ref<godot::ArrayMesh>> by_path;
+	int loaded = 0, failed = 0;
+};
+
+// real_gr2_path = AssetResolver 解析后的真实路径。返回共享 ArrayMesh（含材质）。
+// 失败返回 invalid Ref。
+godot::Ref<godot::ArrayMesh> get_static_mesh(const std::string &real_gr2_path,
+		const fmt::AssetResolver &res, StaticMeshCache &cache);
+
+// 退出时清缓存的 Ref<Image>（别拖到 __cxa_finalize）。
+void cleanup_static_object_cache();
+
+} // namespace mtgodot