Wave 3 #41: Connection: Music Assistant (tier-b) — multi-room van audio

[bernardc6]

Wave 3 #41: Connection: Music Assistant (tier-b) — multi-room van audio

Promotes the legacy tier-c docs/catalog/audio-media/music-assistant.md
spec into a tier-b recipe connection at connections/music-assistant/.
Follows the same pattern proven by Wave 3 #35 Frigate / #36 Starlink /
#37 DNS blocker / #38 NAS / #39 Teltonika / #40 Peplink. Music
Assistant is the multi-room van audio slice of RoamCore — provider-
agnostic (Spotify, Apple Music, TuneIn, local files, Chromecast /
AirPlay / Sonos receivers) unified audio orchestrated by HA — and the
recipe documents both the Path A HA add-on (recommended for HAOS
installs; auto-discover via zeroconf) and Path B external MA server
(recommended for fleet installs + non-HAOS hosts; via
ghcr.io/music-assistant/server).

This slice does NOT edit any peer connection folder, nor the build-
status row for any other connection. Only the new music-assistant
files + the scripts/check.sh wire-up + the legacy-doc supersession
banner + the new build-status row for Wave 3 #41 + the
docs/reference/rc-entity-naming.md allowed-subsystems update (adding
the media subsystem alongside this slice).

Context:

• Wave 3 Wave 3 #37: Connection: DNS blocker (Pi-hole / AdGuard Home, tier-b) — network-wide DNS ad blocker #41 ship; promoted from tier-c legacy spec
• HACS-only install: MA is fetched from
  music-assistant/hass-music-assistant via HACS → Repositories → Add
  (HA core does NOT include Music Assistant; install.hacs: true is
  honest upstream truth, NOT a tier-a marker for RoamCore)
• install.config_flow: true is also honest upstream truth (the
  upstream HACS integration has a config_flow since 2023) — NOT a
  tier-a marker for RoamCore (we ship no RoamCore-owned config_flow.py)
• Per-zone rc_media_zone_* template media_player aliases map the
  upstream media_player.mass_* entities into the vendor-neutral
  rc_media_* family
• 14 contract entities: 3 media_player zones + 1 binary_sensor + 6
  sensors + 2 buttons + 1 select
• 8 OpenClaw queries + 7 summary keys
• 4 tier_warnings honesty markers (no_real_music_assistant_for_
  integration_test, recipe_depends_on_user_running_ma, optional_
  provider_choice_spotify_apple_music_local_files, hacs_required_
  for_integration)

Changes:

• New connections/music-assistant/connection.yml (tier-b manifest;
  mirrors Peplink manifest shape verbatim with music-assistant
  substitutions: media category, beta status, 0.1.0 version, audio
  icon, recipe connection_kind, 14 contract tiles, 8 OpenClaw
  queries, 7 OpenClaw summary keys, 4 tier_warnings, HACS-only
  install, HACS default store listed for ha_integration_domain).
• New connections/music-assistant/init.py (DOMAIN marker stub;
  mirrors Peplink init.py shape with music-assistant-specific
  docstring describing Path A + Path B + the rc_media_* contract
  family + the pause_all / resume_last affordances).
• New connections/music-assistant/README.md (folder overview;
  mirrors Peplink README shape with music-assistant-specific setup
  recipe + cross-references to Starlink + Teltonika + Peplink +
  MQTT siblings).
• New connections/music-assistant/docs/recipe.md (~1056-line howto;
  required sections §1 What is Music Assistant in RoamCore? / §2
  Prerequisites / §3 Path A — HA add-on / §4 Path B — external MA
  server / §5 RoamCore contract entities / §6 Automations (6
  automations: Stealth auto-pause, Travel motion-resume, Boost zone-
  default-volume, inverter-SOC power-aware pause, TTS-zone-pinning,
  remember-last-played) / §7 Provider setup notes (Spotify / Apple
  Music / TuneIn / local-files / Chromecast / AirPlay / Sonos) /
  §8 Troubleshooting (8 entries) / §9 Privacy / §10 Promoting to
  tier-a).
• New connections/music-assistant/tests/test_connection_yml.py (7
  manifest-honesty tests: id matches folder / tier-b without tier-a
  markers / docs recipe published / category matches legacy doc /
  dashboard tiles follow rc naming / status reflects no real music-
  assistant / agent pause-all action is allowlisted).
• Modify scripts/check.sh — append a run_if_present entry for
  connections/music-assistant/tests/test_connection_yml.py directly
  after the existing Peplink entry.
• Modify docs/catalog/audio-media/music-assistant.md — add a
  supersession banner at the top pointing at the new connection
  folder (matches the Wave 3 Wave 3 #36: Connection: Starlink (tier-b) — sleep timer + bring-back-up controls #40 Peplink supersession banner shape;
  legacy content below the banner is preserved for historical
  context).
• Modify docs/mvp/features-build-status.md — add a 'Shipped (repo)'
  row for Wave 3 Wave 3 #37: Connection: DNS blocker (Pi-hole / AdGuard Home, tier-b) — network-wide DNS ad blocker #41 mirroring the recent Wave 3 connection-row
  shape (manifest + recipe size + manifest-honesty smoke + contract
  entities + supersession banner + HACS-only install note + PR link
  placeholder PR #N).
• Modify docs/reference/rc-entity-naming.md — add 'media' to the
  Allowed subsystems (recommended set) list alongside this slice
  (the new §media subsystem under which the rc_media_* contract
  family lives).

Verification:

• python3 -m pytest connections/music-assistant/tests/test_connection_yml.py -v
  → 7/7 PASS
• bash scripts/check.sh --core-only
  → ✓ all requested smoke checks passed.

Rollback:

• git revert -m 1 on main
• The legacy docs/catalog/audio-media/music-assistant.md already
  carries a supersession banner pointing at connections/music-
  assistant/, so even post-revert operators have a pointer to the
  new connection folder.
• git branch -d feat/connections/music-assistant + git push origin
  --delete feat/connections/music-assistant once the PR is closed.

Notes for next slice:

• The Music Assistant recipe references the Starlink + Teltonika +
  Peplink + MQTT connection folders as 'companion slices' — keep
  the cross-refs intact as those slices evolve.
• The §6.1 Stealth auto-pause, §6.2 Travel motion-resume, §6.3
  Boost zone-default-volume, §6.4 inverter-SOC power-aware pause,
  and §6.5 TTS-zone-pinning automations are mode-aware and respect
  RoamCore modes — same pattern as the Peplink / Teltonika slices.
• The §10 tier-a promotion outline describes the RoamCore-owned MA
  container image + default provider stub + CI bench container
  needed to flip this to tier-a.