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_TW.md

@@ -171,6 +171,17 @@ docker compose up -d
 
 *注意：公開演示環境，請不要在其中填入任何敏感資訊。*
 
+## 為 AI Agent 而生 🤖
+
+LangBot **從設計上就對 Agent 友善** —— 你的編碼 Agent（Claude Code、Codex、Copilot、Cursor 等）可以一等公民般地操作、擴充和部署 LangBot：
+
+- **MCP Server** —— LangBot 內建 [Model Context Protocol](https://modelcontextprotocol.io/) 端點 `/mcp`，與 HTTP API 對齊，Agent 可程式化管理機器人、流水線、外掛和模型。使用同一套 API Key 鑑權（可在 `config.yaml` 設定全域 Key，或使用使用者 Key），無需登入流程。在 Web 面板的 **API 與 MCP** 分頁中設定。
+- **倉庫內 Skills** —— [`skills/`](skills/) 目錄是使用 LangBot 的**唯一事實來源**：外掛開發、核心開發、端到端測試、部署，以及操作 LangBot / LangBot Space MCP Server。把 Agent 指向這個目錄，它就知道如何動手。
+- **AGENTS.md** —— 每個倉庫都提供 [`AGENTS.md`](AGENTS.md)（軟連結到 `CLAUDE.md`），描述架構、規範，以及「API 變更必須同步更新 MCP Server 和 skills」的約定。
+- **`llms.txt`** —— 面向 LLM 的機器可讀專案上下文已發布在官網。
+
+> **雲端 / 市集：** [LangBot Space](https://space.langbot.app) 同樣開放 MCP Server，Agent 可搜尋和檢視外掛 / MCP / Skill 市集，使用 Personal Access Token 鑑權。
+
 ---
 
 ## 社群