feat: add cs-dust2 React case with two model takes + react kind support

New case cs-dust2 (kind:react): a from-scratch React + three.js 5v5 Dust2 FPS.
Two takes registered: Claude Fable 5 / Claude Code / High (with a hand fix for a
64Hz fixed-step firing bug on high-refresh displays) and Claude Opus 4.8 /
Claude Code / Max (dust2-arena, one-shot). React cases commit source only; the
single file is built from source at deploy time. validate-data.ts now accepts a
React project directory as the declared artifact. AGENTS.md rewritten
English-only with React-case, bare-harness (no skills/plugins) and
artifact-anonymity rules.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

outputs/claude-fable-5/claude-code-high/cs-dust2/index.html

@@ -0,0 +1,15 @@
+<!doctype html>
+<html lang="zh-CN">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>DUST II — 5v5 模拟器</title>
+    <style>
+      html, body, #root { margin: 0; padding: 0; width: 100%; height: 100%; overflow: hidden; background: #0b0e12; }
+    </style>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>