feat(employed): add live job search plugin

[buddywhitman]

Plugin type (required) / 插件类型（必填）

• UI Plugin / 是 UI 插件: the hosted MCP server's search tools carry _meta.ui.resourceUri (ui://employed/results-v1, text/html;profile=mcp-app), so results render as an MCP Apps page where supported. The plugin itself declares no ui.surfaces.
• Standard plugin / 普通插件（非 UI）
• Not applicable / 不适用

Affected plugin name(s) / 涉及的插件名称：employed

What / 改动内容

Adds Employed by Guaq AI as a community plugin (external_plugins/employed/). It does live job search over postings read directly from about 5,000 employers' own applicant-tracking systems (Greenhouse, Lever, Workday, Ashby, SmartRecruiters and more).

• User problem: job boards mix stale and reposted listings. With this plugin you can ask ZCode for live roles by domain, seniority, location, work mode, technology or visa signal, research an employer's hiring, or get a hiring-market brief. Every result links to the employer's own apply page.
• Contents: a remote MCP server (https://jobs.guaqai.me/mcp, Streamable HTTP, OAuth 2.1 with dynamic client registration, so no API key is pasted), 5 skills, 2 agents and 3 commands. The icon is at assets/employed/icon.png (512x512).
• Network, data and side effects: the only destination is https://jobs.guaqai.me/mcp. It receives the filters and ids the agent chooses, any profile fields the user asks to save, and the OAuth token. Account tools change only the signed-in user's own Employed data (profile, tracker, alerts), and only when asked. The plugin has no hooks, no local commands and no workspace file writes. All of this is documented in both READMEs.
• Version: 1.2.0, the same in .zcode-plugin/plugin.json and marketplace.json.
• License and provenance: MIT, all original work by Guaq AI. Source: https://github.com/Guaq-AI/employed-plugins. Privacy policy: https://jobs.guaqai.me/privacy-policy

Testing:

• The same server and skills are in use from Claude, ChatGPT and Copilot.
• The OAuth discovery chain was checked on the live server: a 401 with WWW-Authenticate, then the protected-resource and authorization-server metadata, then registration.
• I have not run it inside ZCode Desktop yet, and would welcome a maintainer check there.

Self-check / 自查清单

• Plugin name is unique kebab-case; new external plugin directory is external_plugins/employed/
• Usage category is set (productivity)
• Plugin type and affected names are declared above
• version is 1.2.0 in BOTH plugin.json and marketplace.json (new plugin)
• README.md (EN) and README_CN.md (中文) are both present and equivalent
• description_i18n has both en and zh-CN
• No secrets, machine-specific paths or private dependencies
• Model, API and network dependencies are documented
• python3 scripts/validate.py (35 plugins OK) and python3 scripts/build_dist.py pass locally; git diff --check is clean

🤖 Generated with Claude Code

[panda920]

✅ Internal validation passed. A ZCode maintainer will review the change next; after acceptance, release checks run separately and this PR is closed automatically.