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

libgr2/include/gr2/gr2.h

@@ -0,0 +1,97 @@
+// libgr2 —— gr2 v6 只读读取器（demo 子集）。
+// 施工文档：docs/steps/M0-gr2-reader.md
+#pragma once
+#include "types.h"
+#include <cstdint>
+#include <cstddef>
+#include <memory>
+#include <optional>
+#include <span>
+#include <string>
+#include <vector>
+
+namespace gr2 {
+
+enum class Magic { Unknown, Bit32_LE, Bit32_BE, Bit64_LE, Bit64_BE };
+
+struct LoadError {
+    std::string stage;   // "header" / "section" / "typetree" / "fileinfo" / ...
+    std::string message;
+};
+
+// T3：通用类型树遍历（gr2dump 打印成员用；不硬编码 struct 布局）
+struct MemberDump { std::string name; int member_type; int array_width; };
+class File;
+std::vector<MemberDump> dump_root_members(const File&);
+
+// 材质视图（类型树遍历 root.Materials → granny_material）。
+// 只读文件名，不解码贴图。diffuse_texture 取 Usage 含 "diffuse" 的 map 的
+// 贴图，退而取第一张；all_textures 是从该材质可达的全部 FromFileName。
+struct MaterialInfo {
+    std::string              name;
+    std::string              diffuse_texture;
+    std::vector<std::string> all_textures;
+    // Metin2/EterGrnLib 渲染态推断（gr2 不带 D3DRS，靠名字 + map 数 + ExtendedData）：
+    int  map_count = 0;      // granny_material.MapCount（可达子材质的 Texture 数）
+    bool alpha_blend = false;// Name 以 "Blend" 开头且 map_count>1（EterGrnLib Material.cpp:233）
+    bool two_sided = false;  // 名字含 2side/twoside/double/leaf/tree/ivy/fence（ExtendedData "Two-sided" 的近似）
+};
+std::vector<MaterialInfo> dump_materials(const File&);
+
+// 已解析、fixup 后的文件。析构释放所有 section 缓冲。
+class File {
+public:
+    static std::optional<File> load(const uint8_t* bytes, size_t len, LoadError* err);
+    static std::optional<File> load_path(const std::string& path, LoadError* err);
+
+    // T1
+    Magic                        magic()        const { return magic_; }
+    uint32_t                     format_version()const { return version_; }   // 期望 6
+    uint32_t                     total_size()    const { return total_size_; }
+    const std::vector<SectionInfo>& sections()   const { return sections_; }
+
+    // T4 —— 完整汇总（内部会按需触发 T5/T6/T7a）
+    const FileInfo&              file_info()     const { return info_; }
+
+    // 展开后的 section 字节（T2 产出）。空 section 返回空 span。调试 / 校验用。
+    std::span<const uint8_t>    section_bytes(size_t i) const;
+
+    // T5 —— bind pose 自洽检查（不依赖 oracle）。返回 max|world_bind·invBind − I|
+    //        阈值策略见 M0-gr2-reader.md T5（noise_floor 前用 1e-3）
+    double                       bind_pose_self_check(int skeleton = 0) const;
+
+    // M2 便捷封装（同文件内的 skeleton + animation）。跨文件（model gr2 + anim gr2）
+    // 用自由函数 gr2::sample_pose(skeleton, animation, t, ...)。anim/skeleton 是 file_info() 索引。
+    bool sample_pose(int anim, float t, int skeleton,
+                     std::vector<Mat4>& world_pose, std::vector<Mat4>& skin) const;
+    bool bind_pose(int skeleton, std::vector<Mat4>& world_pose, std::vector<Mat4>& skin) const;
+
+private:
+    File() = default;
+    Magic                    magic_ = Magic::Unknown;
+    uint32_t                 version_ = 0;
+    uint32_t                 total_size_ = 0;
+    std::vector<SectionInfo> sections_;
+    FileInfo                 info_;
+    // 内部：section 缓冲、root object 指针、类型树 —— 放 .cpp 的 Impl
+    struct Impl;
+    std::shared_ptr<Impl>    impl_;
+
+    friend std::vector<MemberDump> dump_root_members(const File&);
+    friend std::vector<MaterialInfo> dump_materials(const File&);
+};
+
+// ── M2：姿势采样（model 的 skeleton + anim 的 tracks 可来自不同 gr2）──────
+// Granny 语义、行主序、平移在 elem 12..14：
+//   world[i] = Composite(local[i]) · (parent<0 ? sk.initial_placement : world[parent])
+//   skin[i]  = sk.bones[i].inverse_world · world[i]
+// tracks 按骨骼名匹配 sk；无匹配的骨骼用 sk 的 bind LocalTransform。
+void sample_pose(const Skeleton& sk, const Animation& an, float t,
+                 std::vector<Mat4>& world, std::vector<Mat4>& skin);
+void bind_pose(const Skeleton& sk, std::vector<Mat4>& world, std::vector<Mat4>& skin);
+
+// 打印辅助
+const char* magic_name(Magic);
+const char* compression_name(uint32_t section_format);  // 0=none 1=Oodle0 2=Oodle1
+
+} // namespace gr2