v1.9.0

chore(release): bump robot-md to 1.9.0 — Spec A close-out

What's Changed

• feat(cookbook): rewrite beat 6 — discover/install actuator + beat 7 verify registry record by @craigm26 in #55
• phase-3: scaffold /case-studies/ + Bob inaugural entry; cookbook beat-7 → RPN-000000000002 by @craigm26 in #57
• fix(cli): source version from importlib.metadata by @craigm26 in #58
• fix(cli): bump rcan_version template from 3.0 to 3.2 by @craigm26 in #59
• fix(cli): filter pispbe-* Pi ISP nodes from v4l2 camera list by @craigm26 in #60
• feat(doctor): explain /dev/ttyACM gateway-user ownership as informational warn by @craigm26 in #61
• feat: Spec A Tasks 13-17 — install_backend init phase by @craigm26 in #62
• feat: Spec A Tasks 18-22 — install-gateway subcommand by @craigm26 in #63
• docs: Spec A Task 28 — rewrite Claude Code install page by @craigm26 in #64

Full Changelog: v1.8.0...v1.9.0