hearth v0.9.0 - Ready

Pre-1.0 hardening. New hearth-doctor command runs a one-shot health check (Ollama, audit DB, disk, services) with a pass/warn/fail checklist and a non-zero exit on failure. mapd's POST endpoints now have a per-IP sliding-window rate limiter (remote callers only; localhost stays unlimited), returning 429 over the limit. The command cockpit stacks into a single column on phones/tablets. Docs: https://ericfinland.github.io/hearth/