feat: MCP server + in-repo skills (agent-friendly platform) (#2269)

* feat(api): support global API key from config.yaml (api.global_api_key)

Accept a config-defined global API key anywhere a web-UI key is accepted
(X-API-Key / Bearer), with no login session and no DB record. Useful for
automated deployments and AI agents (HTTP API + MCP). Defaults to empty
(disabled); does not require the lbk_ prefix.

- templates/config.yaml: add api.global_api_key with security notes
- service/apikey.py: verify_api_key checks global key first (constant-time)
- docs/API_KEY_AUTH.md: document the global key + security guidance
- tests: cover global-key match, prefix-free, fallback-to-db, disabled

* feat(mcp): expose LangBot management as an MCP server at /mcp

Add an MCP (Model Context Protocol) server so external AI agents can manage a
LangBot instance. Reuses the same API-key auth as the HTTP API (including the
config.yaml global API key).

- pkg/api/mcp/server.py: FastMCP server wrapping the service layer; 21 curated
  tools across system/bots/pipelines/models/knowledge/mcp-servers/skills
- pkg/api/mcp/mount.py: ASGI dispatcher fronting Quart; authenticates /mcp
  requests with an API key, runs the streamable-HTTP session manager lifespan
- controller/main.py: serve the wrapped ASGI app via hypercorn (was run_task)
- web: new 'MCP' tab in the API integration dialog showing endpoint, auth, and
  client config; i18n for 8 locales
- tests/manual/mcp_smoke.py: e2e check (401 unauth, list tools, call tools)

Tool surface is intentionally curated (not all ~25 route groups) to keep the
agent surface small, safe, and maintainable. Extend deliberately.

* feat(skills): add in-repo skills/ as the single source of truth

Migrate the agent skills + QA/e2e test harness from the (now archived)
langbot-app/langbot-skills repo into LangBot/skills/, and add four new skills.

Migrated:
- langbot-plugin-dev, langbot-testing (e2e), langbot-env-setup,
  langbot-skills-maintenance, langbot-eba-adapter-dev
- the bin/lbs CLI (src/, test/, scripts/, schemas/, qa-agent-docs/)

New:
- langbot-dev      core backend + web development
- langbot-deploy   Docker/K8s deployment + config.yaml + global API key
- langbot-mcp-ops  operating the LangBot MCP server (/mcp)
- langbot-space-ops operating the Space marketplace MCP server

- src/cli.ts repoRoot(): recognize the skills assets root (skills.index.json +
  bin/lbs) so the CLI works when nested inside the LangBot repo
- README.md: unified skill catalog; skills.index.json regenerated

Parity with source verified: bin/lbs validate + node test suite match the
source repo (only the uncommitted .lbpkg build-artifact fixture differs).

* docs(agents): document agent-facing surfaces + API/MCP/skills sync rule

* docs(readme): add 'Built for AI Agents' section across all locales

Highlight MCP server, in-repo skills (single source of truth), AGENTS.md
sync rule, and llms.txt. Cross-link LangBot Space MCP marketplace.

* style(mcp): fix ruff format + prettier lint in MCP server and API panel

* style(web): prettier format MCP i18n locale entries

* docs(skills): note MCP instance control in dev/testing skills

All development-guidance skills now point to the LangBot instance MCP
server (/mcp) and the Space marketplace MCP server, reusing API keys.

skills/qa-agent-docs/qa-agent/README.md

@@ -0,0 +1,46 @@
+# LangBot QA Agent 文档导航
+
+这个目录记录 `langbot-skills` 当前的 QA 方向和后续建设顺序。
+
+## 当前判断
+
+当前重点是 LangBot 的黑盒 E2E QA，不是 LangBot core 的单测覆盖率建设。
+
+`langbot-skills` 要帮助开发者和 QA agent 做接近人工测试的 WebUI 验证：
+
+- 打开真实 LangBot WebUI；
+- 按用户路径点击和输入；
+- 检查用户可见的 UI 结果；
+- 查看 console、network、截图、后端和前端日志；
+- 输出可复用的测试报告；
+- 把稳定 feature 路径沉淀为 case；
+- 把重复故障沉淀为 troubleshooting。
+
+API 和 curl 只做诊断。它们可以解释失败原因，但不能让一个 UI case 通过。
+
+## 文档状态
+
+| 文档 | 状态 | 用途 |
+| --- | --- | --- |
+| `04-black-box-e2e-roadmap.md` | 当前主路线图 | 决定下一步建设什么。 |
+| `03-agent-browser-qa-principles.md` | 当前原则文档 | 定义 browser-first QA 的通过标准。 |
+| `02-log-guard-plan.md` | 当前活跃设计 | 设计 `lbs test report` 里的日志守卫。 |
+| `../user-guide.md` | 当前使用手册 | 开发者日常使用。 |
+| `00-technology-options.md` | 背景文档 | 选择 Computer Use、Playwright MCP 或未来直接 Playwright。 |
+| `01-qa-agent-harness-plan.md` | 历史规划，部分过时 | 解释最初分层和目录设计；使用前先看状态说明。 |
+
+## 已过时的点
+
+`01-qa-agent-harness-plan.md` 还保留早期规划状态。现在结构化 cases、
+结构化 troubleshooting、`validate`、`index`、`lbs test plan` 都已经落地。
+
+已经补上第一版 `lbs test start`、`lbs test run`、`lbs test report` 和日志守卫文件扫描。
+`webui-login-state`、`pipeline-debug-chat` 已经绑定直接 Playwright 自动化脚本。后续重点是：
+
+- 报告 evidence 字段继续打磨；
+- case success/failure signal 和日志守卫规则继续补充；
+- 报告产物和 evidence 约定；
+- 等 LangBot 当前开发状态稳定后跑真实 sample report。
+
+不要再把旧阶段列表当成当前 source of truth。后续排序以
+`04-black-box-e2e-roadmap.md` 为准。