feat(mcp): implement MCP server framework

[galligan]

Problem

@outfitter/mcp is not implemented. Blocks building any MCP-based tools. Core to the dual-transport (CLI + MCP) architecture.

Required

Per SPEC.md and PLAN.md:

• createMcpServer(options) - Factory for MCP server
• defineTool<I, O, E>() - Type-safe tool registration
• defineResource() - Resource registration
• Pagination adapter for cursor-based results
• Error translation (TaggedError → MCP error responses)
• Transport-agnostic handler invocation

Dependencies

• @modelcontextprotocol/sdk
• @outfitter/contracts
• @outfitter/logging

Acceptance Criteria

• McpServer wraps @modelcontextprotocol/sdk
• Tools invoke handlers with HandlerContext
• Errors translated to MCP error format
• Pagination cursors work across MCP calls
• Integration test with CLI harness