feat(spexcode-atlas): add SpexCode Atlas plugin

[shuxueshuxue]

What / 改动内容

Adds SpexCode Atlas (spexcode-atlas 0.1.0, category developer-tools): one skill, atlas, that reads a repository into a SpexCode spec tree (.spec/, one spec.md per part stating what it is for and which file it governs), draws a diagram for each part worth one, and hands over the whole tree as one self-contained HTML page that opens from disk.

新增 SpexCode 图集（spexcode-atlas 0.1.0，分类 developer-tools）：一个 skill atlas，把代码仓库整理成 SpexCode 规格树，给值得配图的部分画图，最后交出一个直接从磁盘打开的单文件网页。

• For a whole repository the skill submits one dynamic workflow (skills/atlas/atlas.dwf.ts) with CreateWorkflow: survey, parallel spec writers, a spex spec lint gate, a planner, parallel cartographers each gated on spex diagram check, an independent reader whose findings are re-checked by separate subagents, then commit .spec/ and publish the page as the run's artifact. Every check is a world.run the script branches on, never a subagent's claim.
• On a ZCode build without CreateWorkflow, the skill does the same job turn by turn and tells the user so.
• Files added: plugins/spexcode-atlas/ (manifest, skill, workflow, README.md, README_CN.md), assets/spexcode-atlas/icon.png (256×256, transparent), and the marketplace.json entry.

Dependencies and side effects (also in both READMEs): Node.js ≥ 22 and npm; SpexCode runs only through npx -y -p spexcode@next spex … (downloads from the npm registry, no global install); writes .spec/ in the current repository and commits it with .spec as the only path; writes spexcode-atlas.html at the root, uncommitted; no MCP server, no hooks, no remote service, no telemetry. MIT, source: https://github.com/shuxueshuxue/spexcode.

How it was tested / 测试方式

• python3 scripts/validate.py → OK: 19 plugin(s) validated; python3 scripts/build_dist.py → plugins/spexcode-atlas/0.1.0/plugin.zip (13.8 KB); python3 -m unittest discover -s tests → OK; git diff --check clean.
• ZCode's own plugin installer (feat/dynamic-workflow b8b352047) with a copy of this branch added as a directory marketplace: installs spexcode-atlas 0.1.0 with no diagnostics; zcode plugins lists it enabled with 1 skill, zcode skills list lists spexcode-atlas:atlas.
• The same skill and workflow were run end to end in the ZCode desktop app on Linux (feat/dynamic-workflow) on psf/requests, which had no .spec/: 7 phases, 2 h 2 min, 39 subagents, GLM-5.2. Checked outside ZCode afterwards: two commits touching only .spec/, 39 nodes, spex spec lint 0 errors, 21/21 diagrams pass spex diagram check, the page opens from disk with no network requests. One node was skipped on purpose after its cartographer escalated and the main agent answered.

Self-check / 自查清单

• Plugin name is unique kebab-case; directory is plugins/spexcode-atlas/ / 插件名唯一且 kebab-case，目录为 plugins/spexcode-atlas/
• version 0.1.0 in BOTH plugin.json and marketplace.json / 两处版本号一致
• README.md (EN) and README_CN.md (中文) both added and equivalent / 中英文 README 均已添加且语义一致
• description_i18n has both en and zh-CN
• No secrets, machine-specific paths, or private dependencies / 不含密钥、机器专属路径或私有依赖
• Model/API/network dependencies documented / 模型、API、网络依赖已写明
• python3 scripts/validate.py and python3 scripts/build_dist.py pass locally / 本地校验与构建均通过

Opened as a draft for the SpexCode maintainers' own review first. The whole-repository path needs a ZCode release that ships dynamic workflows; until then the skill's turn-by-turn path applies.