Add AGENTS.md + tighten contribution flow

- AGENTS.md: public contributor/agent guide (two-file rule, model-centric
  ids, one-entry-per-harness, bilingual notes, screenshot proof)
- PR template: require a generation proof screenshot; drop the manual
  update-registry step; add id-naming and no-README-edit checks
- CI: PRs only run validate-data; pushes to main auto-regenerate and commit
  the README registry (contents:write on that job, [skip ci], no loop)
- README/update-registry: reflect auto-synced registry; fix stale 'two cases'
  -> three (mythos-craft, pelican-cycling, skeleton-watch); link AGENTS.md

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

AGENTS.md

@@ -0,0 +1,99 @@
+# AGENTS.md
+
+Guidance for humans and coding agents contributing to **NAGI BENCH** data
+(https://bench.nagi.fun/). Read this before opening a PR. 中文说明见每节。
+
+## What this repo is / 这个仓库是什么
+
+The **public data repo**: community-contributed *one-shot* LLM eval artifacts.
+You add a model's raw output for a case; the site renders it verbatim. This repo
+holds **data only** — no site code, no build of the page you see.
+
+公开**数据仓库**：社区贡献的「一次生成」LLM 测评产物。你提交某模型在某个 case 上的
+原始输出，站点会原样渲染。这里只有**数据**，没有站点代码。
+
+## A contribution is exactly two files / 一次贡献就两个文件
+
+1. **The artifact** — the raw model output, dropped at
+   `outputs/<artifactDir>/<case-id>.<ext>` (e.g. a single-file `.html` or `.svg`).
+2. **The registration** — `models/<model-id>.json` declaring it.
+
+Do **not** touch anything else. In particular:
+
+- **Do not edit `README.md` / `README.en.md`.** The Registry tables are
+  generated from `models/*.json` and synced automatically after merge. Hand
+  edits are overwritten. （**不要改 README**，注册表是自动生成并在合并后自动同步的。）
+- **Do not edit `cases.json`.** Cases are maintainer-owned.（case 由维护者管理。）
+
+## `models/<model-id>.json` schema
+
+```jsonc
+{
+  "label": "DeepSeek V4 Flash",   // human-facing model name (required)
+  "vendor": "DeepSeek",            // who makes the model (required)
+  "harness": "Reasonix",           // the tool/agent/UI you ran it in (required)
+  "effort": "Max",                 // thinking budget / effort level (required)
+  "artifactDir": "deepseek-v4-flash/reasonix-max", // optional; defaults to <model-id>
+  "order": 50,                      // optional display sort
+  "runs": {
+    "skeleton-watch": {
+      "note": {                     // REQUIRED, bilingual, zh first, no emojis
+        "zh": "在 Reasonix 中以 DeepSeek V4 Flash（Max）一次生成，未修改。",
+        "en": "One-shot by DeepSeek V4 Flash (Max effort) in Reasonix, unmodified."
+      },
+      "contributor": "your-github-username"
+    }
+  }
+}
+```
+
+### Naming rules / 命名规则
+
+- **The filename IS the entry id** — lowercase letters, digits and dashes only
+  (`deepseek-v4-flash-reasonix`). It is the **stable voting key** and the default
+  `outputs/` folder, so name it after the **model**, not the harness. Bad:
+  `reasonix-reasonix-max`. Good: `deepseek-v4-flash-reasonix`.
+  （文件名即条目 id，是稳定投票主键——按**模型**命名，别按 harness 命名。）
+- `artifactDir` may be one or two dash-case segments
+  (`deepseek-v4-flash/reasonix-max`); set it when several entries share a model
+  folder. Leave it out to default to the id.
+
+### One entry per (model × harness × effort) / 一个组合一个条目
+
+The same model under a different **harness** or **effort** is a **separate**
+`models/*.json` file, not an extra variant inside an existing one. "Codex",
+"Cursor", "Claude Code", "AntiGravity" name the **harness**, never the model.
+（同一模型换 harness 或 effort = **新建** JSON，不要塞进现有条目。）
+
+### The `note` is required and bilingual / note 必须双语
+
+Every run needs `note.zh` + `note.en` documenting provenance: which harness,
+which effort, one-shot or fixed. If you applied any fix, say where the bug was
+and what you changed. **No emojis anywhere** (hard rule). zh first.
+
+## Before you open the PR / 提交前
+
+```bash
+bun scripts/validate-data.ts   # the exact schema check CI runs
+```
+
+This enforces: dash-only ids, required bilingual `note`, declared artifacts
+exist and are non-empty, no orphan files under `outputs/`. Green here = green CI.
+
+You do **not** need to run `update-registry.ts` — README is synced for you after
+merge.（不需要手动跑 update-registry，README 合并后自动同步。）
+
+### Attach a screenshot / 附一张截图
+
+The PR template asks for a **screenshot of the generation** — your harness/IDE
+showing the model name + effort while producing this artifact. It is the proof
+that the declared `harness` / `model` / `effort` are real. Paste it into the PR
+body (GitHub hosts it); **do not commit image files** into the repo.
+（PR 里贴一张**生成过程截图**作为「确实用了这套 harness + 模型 + effort」的凭证，
+直接贴进 PR 正文，不要把图片提交进仓库。）
+
+## Conventions / 约定
+
+- No emojis in any data, note, or UI-bound text.
+- `outputs/` files are served verbatim in a sandboxed iframe. Keep them
+  self-contained; external resources should be well-known CDNs only.