Add packages/types/src/federation/ with Zod v4 schemas and inferred TS types for the M3 federation wire protocol. Includes verbs constant, request schema, list/get/capabilities response factories, _source tag helper, and typed error envelope + exception hierarchy. 46 unit tests; typecheck, lint, and format:check all green. Closes #462 Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>