M4: художественный конвейер

- scripts/build-art.mjs: все спрайты игры собираются из исходников,
  а не кладутся руками. Лица карт растеризуются из векторов,
  рубашка/стол/панели/кнопки нарисованы SVG-ом прямо в скрипте
- 36 лиц 220x320 + рубашка, автоатлас 2048x2048, обрезка выключена
  (раскладка рассчитывает на точный размер карты)
- девятипатчевые плитки 120x120 с рамкой 40
- фон стола 540x960, рисуется в 2x — градиенту детализация не нужна,
  а памяти под текстуру уходит вчетверо меньше
- исходные векторы перенесены из local/ в art-src/cards
- ATTRIBUTION.md: LGPL-3.0, атрибуция обязательна; там же написано,
  что менять, если такая лицензия не подходит для релиза

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/TECHNICAL.md

@@ -41,8 +41,8 @@ assets/
     card.prefab               one playing card, face or back
     ...
   art/
-    cards/                    36 faces + back, atlased
-    ui/                       panels, buttons, table surface
+    cards/                    36 faces + back, packed into cards.pac (2048²)
+    ui/                       table surface, nine-slice panels and buttons
   scripts/
     core/                     PURE TS — no engine imports
       cards/                  Suit, Rank, Card, Deck
@@ -62,8 +62,10 @@ tests/
   core/                       vitest specs against assets/scripts/core
   support/                    position fixtures and the state invariant checker
   tools/                      measuring tools, not part of the suite
+art-src/cards/                vector sources for the card faces (LGPL, kept)
 docs/                         specs, this file, plan, decisions
 local/                        scratch art storage; contents get consumed
+scripts/                      build and check tools run through npm
 extensions/cocos-code-mode/   editor tool server
 ```
 
@@ -155,6 +157,35 @@ Scripts and other text assets are written to disk directly and picked up by the
 editor's asset watcher. Scenes and prefabs are authored through the tools —
 never by hand-editing the `.scene`/`.prefab` JSON.
 
+### Art
+
+```bash
+npm run build:art
+```
+
+Regenerates every sprite in `assets/art` from source. Card faces are rasterised
+from the vectors in `art-src/cards`; the card back, table and UI chrome are
+authored as SVG inside [`scripts/build-art.mjs`](../scripts/build-art.mjs) and
+rasterised from there, so a colour or radius is changed in one readable place
+rather than in a binary.
+
+Fixed numbers the layout depends on:
+
+| | |
+|---|---|
+| Card sprite | 220 × 320 px |
+| Nine-slice border | 40 px on 120 × 120 tiles |
+| Table background | 540 × 960, drawn at 2× |
+
+Card sprite frames have trimming switched off, because layout maths assumes
+every card rect is exactly 220 × 320. Card faces are named `<rank>_of_<suit>`,
+matching `Card.assetName` — that string is the only contract between the rules
+core and the art.
+
+Licence: the faces are LGPL-3.0 and attribution is mandatory. See
+[`assets/art/cards/ATTRIBUTION.md`](../assets/art/cards/ATTRIBUTION.md), which
+also explains what would have to change to drop the dependency.
+
 ### Builds
 
 Web: `web-mobile` template. Mobile: ASTC textures per [ART.md](ART.md), PNG for