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

docs/reference/README.md

@@ -0,0 +1,32 @@
+# reference/ — archived from xrender-poc
+
+These docs come from **`xrender-poc`**, the bgfx-based rendering POC that was
+**retired on 2026-08-29** in favour of the Godot route (this repo). See
+[`../MIDREVIEW.md`](../MIDREVIEW.md) for the decision.
+
+They are kept because the reverse-engineering knowledge is route-independent and
+still authoritative:
+
+| file | what's still useful |
+|---|---|
+| `steps/M0-gr2-reader.md` | the entire `.gr2` v6/v7 format breakdown that `libgr2` implements — header, sections, Oodle1, self-describing type tree, `granny_transform`, `OldCurveType` B-splines, the "明确不做" table. **`libgr2` is vendored here now** (`../../libgr2`). |
+| `steps/00-oracle.md` | how the Wine + MinGW Granny oracle works — the ground truth for `libgr2` numeric verification. Oracle harness vendored at `../../oracle/`. |
+| `steps/M1-static-render.md` | material-binding chain (`granny_material` → `.Maps[].Map` → `granny_texture.FromFileName`), DDS/DXT decode, the bgfx-era gotchas. The material logic maps 1:1 onto `m2_material.cpp` here. |
+| `steps/M2-anim-skinning.md` | CPU LBS formula, `sample_pose` retarget-by-bone-name, the Granny normal-transform (plain 3×3, **no** inverse-transpose) — same math the GDExtension uses. Numeric gates vs Granny (≤6.5e-5). |
+| `steps/M3-mobile.md` | iOS/Android notes from the bgfx shells — historical; Godot handles platform now. |
+| `steps/M4-realistic-load.md` | eterpack / full-load plan — deferred in both routes. |
+| `PLAN.md` | the bgfx-route master plan. §01 (go/no-go criteria, "工程性延期 vs 方案性死路"), §05 (format findings), §07 (visual-diff layering) are still the shared vocabulary. |
+| `DEMO-PLAN.md` | bgfx RHI demo design record. Mostly superseded; kept for the shader/material-stage analysis. |
+
+**Relative paths inside these files** (`../libgr2`, `oracle/`, `test/golden/…`,
+`engine/…`, `app/…`) refer to the old xrender-poc layout. The mapping:
+
+| old (xrender-poc) | now (mtgodot-poc) |
+|---|---|
+| `libgr2/` | `libgr2/` (vendored, unchanged) |
+| `formats/` | `formats/` (vendored) |
+| `oracle/` | `oracle/` (vendored; `oracle.exe` + `granny2_x64.dll` rebuilt locally) |
+| `tools/{gr2dump,gr2fuzz,oracle_diff}` | `tools/` (build with `-DMTGODOT_BUILD_TOOLS=ON`) |
+| `engine/`, `app/`, `platform/`, `third_party/` | **dropped** — Godot + the GDExtension in `extension/` replace them |
+| `test/golden/*.png` (bgfx shots) | `test/bgfx-reference/` (cross-check images) |
+| `test/{noise_floor,m2-numeric}.json`, `assets.list` | `test/` (vendored baselines) |