feat: upgrade company context graph primitives, brief, and MCP tools

[G9Pedro]

Summary

• add five new built-in primitives in kernel registry: org, team, pattern, relationship, and strategic_note
• extend existing built-ins (decision, lesson, person, agent, client, project, policy) with additive company-context fields and defaults
• introduce CompanyContext in kernel types and include companyContext in WorkgraphBrief
• enrich orientation brief generation with a derived company context view (org/teams/clients/recent decisions/patterns/actor profile)
• add MCP tools:
  • workgraph_company_context
  • workgraph_create_decision
  • workgraph_record_lesson
  • workgraph_record_pattern
• update starter kit seeding to include a default org primitive at orgs/company.md
• add/update kernel + MCP tests to validate new schema, brief payload, and tool registration/behavior
• refresh schema drift snapshot and harden webhook trigger assertions to validate webhook-specific outbox records

Testing

• pnpm run test
• pnpm run build