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.

README_KO.md

@@ -155,6 +155,17 @@ docker compose up -d
 
 *참고: 공개 데모 환경입니다. 민감한 정보를 입력하지 마세요.*
 
+## AI 에이전트를 위한 설계 🤖
+
+LangBot은 **설계 단계부터 에이전트 친화적**입니다 —— 코딩 에이전트(Claude Code, Codex, Copilot, Cursor 등)가 일급 지원으로 LangBot을 운영·확장·배포할 수 있습니다:
+
+- **MCP 서버** —— LangBot은 내장 [Model Context Protocol](https://modelcontextprotocol.io/) 엔드포인트 `/mcp`를 제공하며, HTTP API와 동일하게 미러링되어 에이전트가 봇·파이프라인·플러그인·모델을 프로그래밍 방식으로 관리할 수 있습니다. 동일한 API 키로 인증하며(`config.yaml`에 전역 키 설정 또는 사용자 키 사용) 로그인 절차가 필요 없습니다. 웹 패널의 **API & MCP** 탭에서 설정합니다.
+- **저장소 내 Skills** —— [`skills/`](skills/) 디렉터리는 LangBot 작업의 **단일 진실 공급원**입니다: 플러그인 개발, 코어 개발, E2E 테스트, 배포, LangBot / LangBot Space MCP 서버 운영. 에이전트를 이 디렉터리로 안내하면 빌드 방법을 알게 됩니다.
+- **AGENTS.md** —— 모든 저장소에는 [`AGENTS.md`](AGENTS.md)(`CLAUDE.md`로 심볼릭 링크)가 있으며 아키텍처, 규약, 그리고 API 변경 시 MCP 서버와 skills를 동기화해야 한다는 규칙을 설명합니다.
+- **`llms.txt`** —— LLM을 위한 기계 판독 가능한 프로젝트 컨텍스트가 웹사이트에 게시되어 있습니다.
+
+> **클라우드 / 마켓플레이스:** [LangBot Space](https://space.langbot.app)도 MCP 서버를 제공하여 에이전트가 Personal Access Token으로 인증해 플러그인 / MCP / Skill 마켓플레이스를 검색하고 조회할 수 있습니다.
+
 ---
 
 ## 커뮤니티