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/m2_material.h

@@ -12,6 +12,7 @@
 namespace godot {
 class ShaderMaterial;
 class Texture2D;
+class ImageTexture;
 } // namespace godot
 
 namespace mtgodot {
@@ -28,8 +29,31 @@ struct MaterialDesc {
 	BlendMode blend = BlendMode::Opaque;
 	float alpha_scissor = 0.5f;
 	bool two_sided = true; // winding not yet verified per-model
+	// GPU skinning: LBS with FULL per-bone affine matrices in the vertex shader
+	// (no Skeleton3D -> no quaternion orthonormalization -> shear preserved).
+	// `bones_tex` is RGBAF, size 3 x bone_count; columns 0..2 = the 3 columns of
+	// the row-vector skin matrix (see metin2_model.cpp::gpu_skin).
+	bool skinned = false;
+	godot::Ref<godot::ImageTexture> bones_tex;
+
+	// Sphere-map specular — port of CGrannyMaterial::__ApplySpecularRenderState
+	// (EterGrnLib/Material.cpp:305). Opaque armor gets a metallic highlight from a
+	// camera-space reflection-vector lookup into a shared sphere map, added on top
+	// of the lit diffuse:
+	//     out.rgb = tex.rgb*modulate  +  (tex.a * spec_power) * sphere(reflect_uv)
+	// Client enables this per skin-part only when the equipped body-armor item's
+	// item_proto `bSpecular > 0` (power = bSpecular/100); the base body is flat.
+	// Dormant here until an equipment layer feeds a power: spec_power <= 0 ->
+	// the shader branch is skipped and output is byte-identical to before.
+	godot::Ref<godot::Texture2D> spec_map; // shared sphere map; null -> disabled
+	float spec_power = 0.0f;               // fSpecularPower (D3DRS_TEXTUREFACTOR.a); 0 = off
 };
 
 godot::Ref<godot::ShaderMaterial> make_material(const MaterialDesc &d);
 
+// Drop the extension-owned shader cache before GDExtension teardown. Materials
+// still alive in the scene keep their own Ref, so this only removes the static
+// lifetime that otherwise survives Godot's leak check.
+void cleanup_material_shaders();
+
 } // namespace mtgodot