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

build-android.sh

@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+# Cross-compile the mtgodot GDExtension for Android (OnePlus 13 / arm64 / Vulkan).
+# Produces project/bin/libmtgodot.android.template_{debug,release}.arm64.so.
+#
+# On-device run + APK export is the rest of BACKLOG F2; see docs/PLATFORMS.md.
+#
+# Needs the Android NDK. Point at it with ANDROID_NDK_ROOT (or install via
+# Android Studio → SDK Manager → NDK, default ~/Library/Android/sdk/ndk/<ver>).
+set -euo pipefail
+cd "$(dirname "$0")"
+
+CONFIG="${1:-Debug}"                       # Debug | Release
+ABI="${ANDROID_ABI:-arm64-v8a}"
+API="${ANDROID_PLATFORM:-24}"
+BUILD_DIR="build-android"
+JOBS="${JOBS:-$(sysctl -n hw.ncpu)}"
+
+# --- locate the NDK ---
+NDK="${ANDROID_NDK_ROOT:-${ANDROID_NDK_HOME:-}}"
+if [ -z "$NDK" ]; then
+	SDK="${ANDROID_HOME:-${ANDROID_SDK_ROOT:-$HOME/Library/Android/sdk}}"
+	if [ -d "$SDK/ndk" ]; then
+		NDK="$SDK/ndk/$(ls -1 "$SDK/ndk" | sort -V | tail -1)"
+	fi
+fi
+if [ -z "$NDK" ] || [ ! -f "$NDK/build/cmake/android.toolchain.cmake" ]; then
+	echo "Android NDK not found. Set ANDROID_NDK_ROOT to an NDK with" >&2
+	echo "  build/cmake/android.toolchain.cmake (install via Android Studio SDK Manager)." >&2
+	exit 1
+fi
+echo "NDK: $NDK"
+
+if [ ! -f extension/godot-cpp/cmake/android.cmake ]; then
+	echo "godot-cpp submodule missing — git submodule update --init --recursive" >&2
+	exit 1
+fi
+
+cmake -S . -B "$BUILD_DIR" -G "Unix Makefiles" \
+	-DCMAKE_TOOLCHAIN_FILE="$NDK/build/cmake/android.toolchain.cmake" \
+	-DANDROID_ABI="$ABI" \
+	-DANDROID_PLATFORM="android-$API" \
+	-DCMAKE_BUILD_TYPE="$CONFIG" \
+	-DMTGODOT_BUILD_TOOLS=OFF \
+	-DBUILD_TESTING=OFF
+
+cmake --build "$BUILD_DIR" --target mtgodot -j "$JOBS"
+
+echo
+echo "Android ($CONFIG / $ABI) library:"
+ls -la project/bin/libmtgodot.android.*.so