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

gen-debug-keystore.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+# Generate the Android debug keystore Godot's editor settings point at:
+#   ~/Library/Application Support/Godot/keystores/debug.keystore
+# (editor_settings-4.7.tres: export/android/debug_keystore, pass "android").
+# Standard well-known debug credentials — never used for release signing.
+set -euo pipefail
+
+KS_DIR="$HOME/Library/Application Support/Godot/keystores"
+KS="$KS_DIR/debug.keystore"
+
+if [ -f "$KS" ]; then
+	echo "already exists: $KS"
+	exit 0
+fi
+
+KEYTOOL="${JAVA_HOME:+$JAVA_HOME/bin/}keytool"
+command -v "$KEYTOOL" >/dev/null 2>&1 || KEYTOOL=keytool
+
+mkdir -p "$KS_DIR"
+"$KEYTOOL" -genkeypair -v \
+	-keystore "$KS" \
+	-storepass android -keypass android \
+	-alias androiddebugkey \
+	-keyalg RSA -keysize 2048 -validity 10000 \
+	-dname "CN=Android Debug,O=Android,C=US"
+
+echo
+echo "created: $KS"
+echo "Godot editor settings already reference it (export/android/debug_keystore)."