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

formats/terrain_mesh.h

@@ -0,0 +1,38 @@
+// W1 —— 一个区块的地形几何（heightmap -> 顶点 / 法线 / 索引），纯数学、无 godot 依赖。
+// 三角划分与法线照 GameLib/AreaTerrain.cpp CTerrain::GetHeight / CalculateNormal。
+// SHINSOO §9-W1。
+//
+//   129×129 可见顶点，128×128 quad。每个 quad 对角线 = TL->BR（GetHeight 的 h1/h2）。
+//   顶点已做 Metin2(cm,Z-up) -> Godot(m,Y-up) 转换（m2_coord），并加了区块原点。
+#pragma once
+#include <cstdint>
+#include <vector>
+
+#include "terrain_files.h"
+
+namespace fmt {
+
+struct TerrainMesh {
+    static constexpr int VERTS_XY = 129;       // XSIZE+1
+    static constexpr int QUADS_XY = 128;       // XSIZE
+
+    std::vector<float> positions;  // 3/vert，Godot 空间（米，Y-up），含区块原点
+    std::vector<float> normals;    // 3/vert，Godot 空间，单位向量
+    std::vector<float> uvs;        // 2/vert，区块内 [0,1]（用于 splat / 地表贴图）
+    std::vector<int32_t> indices;  // 3/tri，6/quad
+    float min_y = 0, max_y = 0;    // Godot Y（高度）范围，做 custom_aabb / 相机用
+
+    int vertex_count() const { return VERTS_XY * VERTS_XY; }
+    int index_count() const { return QUADS_XY * QUADS_XY * 6; }
+};
+
+// height_scale 从 MapSetting 取（A1 = 0.5）。tile_x/tile_y 决定区块原点。
+// ccw_from_above=true：三角绕序在 Godot 里从上方看为逆时针（默认，若发现背面朝上则传 false）。
+void build_terrain_mesh(const HeightMap& hm, int tile_x, int tile_y, double height_scale,
+                        TerrainMesh& out, bool ccw_from_above = true);
+
+// 与 CTerrain::GetHeight 一致的三角插值。lx/ly = 区块本地厘米（[0, 128*200]）。
+// 返回厘米高度（未转 Godot 单位）。
+double terrain_height_at(const HeightMap& hm, double lx_cm, double ly_cm, double height_scale);
+
+} // namespace fmt