docs(mcp): add agentic guidance docs and integrator FAQ

[trichardswp]

Summary

Continues improvements for MCP documentation and agentic guidance. Adds a new Agentic Guidance section and a root-level integrator FAQ so any agent model can map intent to endpoints and integrate correctly without inferring.

Changes

• New Agentic Guidance section (documentation/agentic-guidance/):
  • Capability Map — intent → endpoint + parameters; leads with "person search is one endpoint" (phone/address/name are all GET /v2/person/).
  • Integration Guide — the prescribed workflow: map intent → read the type document → never infer types from samples → ignore unknown fields → hydrate summaries by id.
  • Entity Shapes by Context — the caveat that the same entity comes back in different shapes per endpoint; defer to the type document for exact fields.
• New integrator FAQ at the documentation root: trial exhaustion, how rate limits apply, what counts as a breaking change.
• Documentation nav updated (Agentic Guidance under MCP Server, FAQ at the bottom). All pages carry lifecycle/topic/keywords facets.