Add MCP rpg_generate tool for ZeroRepo pipeline

[amondnet]

Summary

Create a new MCP tool rpg_generate that exposes the ZeroRepo generation pipeline to MCP clients, and add tool orchestration guidance (Search → Fetch → Explore workflow).

Paper: RPG-ZeroRepo (arXiv:2509.16198)

Tasks

• Define Zod schema for rpg_generate input
• Implement tool handler delegating to ZeroRepo pipeline
• Add tool orchestration guidance for the recommended Search → Fetch → Explore workflow
• Update MCP server registration

Dependencies

• Depends on P2 ZeroRepo pipeline implementation (P2: RPG-ZeroRepo generation pipeline #18)

Acceptance Criteria

• MCP clients can trigger code generation via rpg_generate
• Tool orchestration guide is documented in tool descriptions

Related Files

• src/mcp/server.ts
• src/zerorepo/zerorepo.ts