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/splat.cpp

@@ -0,0 +1,61 @@
+#include "splat.h"
+
+namespace fmt {
+
+void build_splat(const TileMap& tile, int runtime_layer_count, SplatSet& out) {
+    out = SplatSet{};
+    const int S = SPLAT_RAW_XY; // 258
+    const auto& t = tile.raw;   // 258*258
+    if ((int)t.size() != S * S) return;
+
+    // 直方图 + 出现过的图层
+    int maxidx = 0;
+    for (uint8_t v : t) maxidx = std::max(maxidx, (int)v);
+    out.tile_histogram.assign(maxidx + 1, 0);
+    for (uint8_t v : t) out.tile_histogram[v]++;
+
+    const int limit = std::max(runtime_layer_count - 1, maxidx);
+    for (int i = 1; i <= limit; ++i) {
+        if (i >= (int)out.tile_histogram.size() || out.tile_histogram[i] == 0) continue;
+
+        SplatLayer L;
+        L.layer = i;
+        L.alpha.resize(size_t(S) * S);
+        int cov = 0;
+        for (int y = 0; y < S; ++y) {
+            const uint8_t* row = &t[size_t(y) * S];
+            const uint8_t* up = y > 0 ? row - S : nullptr;
+            const uint8_t* dn = y < S - 1 ? row + S : nullptr;
+            uint8_t* a = &L.alpha[size_t(y) * S];
+            for (int x = 0; x < S; ++x) {
+                uint8_t tn = row[x];
+                if (tn == i) {
+                    a[x] = 0xFF;
+                    ++cov;
+                } else if (tn > i) {
+                    bool found = false;
+                    if (x > 0 && row[x - 1] == i) found = true;
+                    else if (x < S - 1 && row[x + 1] == i) found = true;
+                    else if (up) {
+                        if (up[x] == i) found = true;
+                        else if (x > 0 && up[x - 1] == i) found = true;
+                        else if (x < S - 1 && up[x + 1] == i) found = true;
+                    }
+                    if (!found && dn) {
+                        if (dn[x] == i) found = true;
+                        else if (x > 0 && dn[x - 1] == i) found = true;
+                        else if (x < S - 1 && dn[x + 1] == i) found = true;
+                    }
+                    a[x] = found ? 0xFF : 0x00;
+                    if (found) ++cov;
+                } else {
+                    a[x] = 0x00;
+                }
+            }
+        }
+        L.coverage = cov;
+        out.layers.push_back(std::move(L));
+    }
+}
+
+} // namespace fmt