feat(node): add audio_root, gate Music enrichment on it like video_root

musicbay.md's original call — Music needs no root, tag reads are cheap so
just cover the whole shared tree — didn't hold up against a real messy
library: everything under every shared folder got mixed together with no
way to scope Music down to an actual music collection. This adds an
audio_root setting, symmetric to video_root in every respect: signed
operator op (audio_root/audio_root_ack, MNP bumped to 0.10), validated
against a real directory in the group's own roots before a signature is
even asked for, gates tag/cover enrichment exactly like video_root gates
ffprobe/TMDB (nothing runs until it's set, only files under it once it
is), and a set/change fires a one-off sweep of whatever the folder already
contains.

The old trigger — sweep everything the instant "music" joins enabled_apps
— is gone along with the root-less design it belonged to; setting
audio_root is now the trigger, mirroring set_video_root's
enrich_video_root_fn exactly.

Test coverage mirrors the video_root suite: policy (refuse before a
signature round trip, accept/store correctly) and the enrichment gate
itself (nothing without a root, only files under it, sweep on set).

1 files changed, 21 insertions, 8 deletions

diff --git a/packages/meshbay-node/src/meshbay_node/ops.py b/packages/meshbay-node/src/meshbay_node/ops.py
index d439ec3..1da6928 100644
--- a/packages/meshbay-node/src/meshbay_node/ops.py
+++ b/packages/meshbay-node/src/meshbay_node/ops.py
@@ -728,14 +728,6 @@ async def set_enabled_apps(state: dict, group_id: str, apps: list[str]) -> dict:
                                   set_by=state.get("node_user_id", ""))
     ctx["enabled_apps"] = apps
     log.info("Enabled apps for group %s: %s", group_id[:8], ",".join(sorted(apps)))
-    if "music" in apps:
-        # Music has no root of its own to key a sweep off (unlike
-        # set_video_root's enrich_video_root_fn) — turning the app on at all
-        # is the trigger, mirroring that same "sweep what's already there"
-        # need (docs/musicbay.md §2.1, daemon._enrich_music_now).
-        enrich_fn = state.get("enrich_music_now_fn")
-        if enrich_fn:
-            asyncio.ensure_future(enrich_fn(group_id))
     return {"apps": apps, "group_id": group_id}
 
 
@@ -850,6 +842,27 @@ async def set_video_root(state: dict, group_id: str, path: str) -> dict:
     return {"path": path, "group_id": group_id}
 
 
+async def set_audio_root(state: dict, group_id: str, path: str) -> dict:
+    """
+    Same shape as set_video_root above — the Music app's own entry point,
+    added later (docs/musicbay.md's original "no root, works over the
+    whole shared tree" simplification didn't hold up against a real messy
+    library). `path=""` clears it — the Music tab then asks for one to be
+    chosen before anything (including tag/cover enrichment) runs, rather
+    than defaulting to the whole shared index.
+    """
+    roster = _roster(state)
+    ctx = _group_ctx(state, group_id)
+    await roster.set_audio_root(group_id, path, set_by=state.get("node_user_id", ""))
+    ctx["audio_root"] = path
+    log.info("Music root for group %s: %r", group_id[:8], path)
+    if path:
+        enrich_fn = state.get("enrich_audio_root_fn")
+        if enrich_fn:
+            asyncio.ensure_future(enrich_fn(group_id))
+    return {"path": path, "group_id": group_id}
+
+
 # ── Scan settings ────────────────────────────────────────────────────────────
 
 async def set_scan_settings(state: dict, group_id: str, reconcile_interval_secs: float,