Contributor credits, SVG prefetch, integrate Xiaomi MiMo from PR #4

- Runs gain a contributor field (GitHub username); the site renders an
  avatar chip linked to their profile next to each run's notes, and CI
  validates the field. All existing runs are attributed.
- SVG variants of a case are prefetched during idle time, so switching
  model tabs swaps images without a network hiccup.
- Xiaomi MiMo v2.5 Pro (Claude Code, max effort) integrated from PR #4
  with both case runs and provenance notes; README registry tables
  updated.

Co-authored-by: DuJiabao <Jiabao.du@Yunzhisun.com>

models/grok-build.json

@@ -9,7 +9,8 @@
       "note": {
         "zh": "在本地通过 Grok Build（TUI）开发实现；本页为修复版（共改 3 行）。问题一：第 82 行 const WORLD_SEED = 0xAETHER，T/H/R 不是十六进制字符，整段脚本解析即抛 SyntaxError——修复前画面纯黑，只剩 HTML 文字。问题二：贴图集画在 canvas 顶部两行、UV 按左上原点计算，却未设 flipY=false，所有面采样到未绘制的黑色区域——修复前进入世界后近处地形全黑。问题三：forward 向量已指向相机朝向，按键却写成 W 减、S 加——修复前按 W 后退、按 S 前进（A/D 正常）。三处均为一行级修正，其余保持 Grok 原样。",
         "en": "Built locally with the Grok Build TUI; fixed build (3 lines changed). Bug 1: line 82 const WORLD_SEED = 0xAETHER — T/H/R are not hex digits, so the whole script threw a SyntaxError at parse time; before the fix the screen was pure black with only HTML text. Bug 2: the atlas is drawn in the top canvas rows with top-left-origin UVs but no flipY=false, so every face sampled the undrawn black region; before the fix nearby terrain rendered solid black. Bug 3: the forward vector already points where the camera looks, but W subtracted and S added — W walked backward (A/D were fine). One line each; everything else is Grok as-is."
-      }
+      },
+      "contributor": "Nagi-ovo"
     }
   }
 }