feat: add MCP registry integration for create-expert skill-finder

[FL4TLiN3]

Summary

• Add searchMcpRegistry and getMcpServerDetail tools to @perstack/create-expert-skill that search the official MCP registry (registry.modelcontextprotocol.io) for MCP servers matching expert skill requirements
• Add @create-expert/skill-finder expert that uses these tools to investigate registry entries and produce skill-report.md with ready-to-use TOML configuration snippets
• Update coordinator, planner, and definition-writer instructions to integrate skill findings into generated expert definitions
• CLI resolves create-expert-skill server path to absolute for CWD-independent operation

Changes

New files (apps/create-expert-skill/src/)

• lib/mcp-registry-client.ts — Registry API client with pagination (100/page, up to 1000 servers), 10-min in-memory cache, 15s timeout, Zod validation
• tools/search-mcp-registry.ts — searchMcpRegistry tool: space-separated AND keyword matching on name+description, name-priority sorting, deprecated server exclusion
• tools/get-mcp-server-detail.ts — getMcpServerDetail tool: fetches server detail, maps npm packages → mcpStdioSkill, SSE/streamable-http remotes → mcpSseSkill, extracts isSecret env vars for requiredEnv
• 28 unit tests across 3 test files (client, search, detail)

Modified files

• apps/create-expert-skill/src/server.ts / index.ts — Register and export new tools
• apps/create-expert/bin/cli.ts — Resolve create-expert-skill server path to absolute using tomlPath as base, so skill-finder works regardless of CWD
• apps/create-expert/perstack.toml — Add @create-expert/skill-finder expert with dual skills (@perstack/base + @perstack/create-expert-skill), update coordinator/planner/definition-writer instructions for skill integration flow
• e2e/create-expert/create-expert.test.ts — Add assertions for searchMcpRegistry calls, skill-report.md creation, and non-base MCP skill in generated TOML; increase timeout to 900s for extended delegation chain

Test plan

• bun run typecheck — 23/23 pass
• bun run test — 19/19 pass (includes 28 new unit tests)
• bun run format-and-lint — clean
• bun run build — 23/23 pass
• bun run validate:changeset — pass
• E2E: bun test --timeout 900000 e2e/create-expert/create-expert.test.ts — 2/2 pass, 22 expect() calls

🤖 Generated with Claude Code