refactor(mnp)!: one operation for an app's folders, not one per app

`video_root`, `audio_root` and `photo_roots` are gone — the messages, the
signed operations, the handlers, the `ops` wrappers, the three scalars on the
handshake ack, and the client's handlers for their acks. `app_directories`
does the same thing for every application, keyed by the app's own registry
name, and it is what the SPA has been sending.

The three were the same instruction three times, differing only in the key they
wrote and whether they carried a string or a list. That shape is what made
adding an application mean adding a message type, an op, a handler and a widget;
it also meant three validation paths, and the older ones validated nothing —
a typo was stored and then quietly matched no entry, an app showing an empty tab
with no way to tell "misconfigured" from "no files yet".

**What stays, and why.** `Roster.LEGACY_DIR_KEYS` still reads `video_root` and
friends out of `group_settings`: that is a key on an operator's disk, not on the
wire, and a node upgraded into this must find its own configuration. The Search
page still reads its own older cache keys, for the same reason — the cache
outlives a deploy. `CTX_ALIASES` keeps only `chat`, which is the one app whose
second name something still reads.

The two per-app policy test files go with the messages. What only they held —
the real challenge/response path from message to database, which no other test
exercises — is retargeted at `app_directories` in
`test_app_directories_signed.py`, and the handler's own refusals (unknown app,
malformed `directories`, nobody to authorize it) join `test_app_directories.py`.

Node and common suites 1368 passed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AsoWC3GmhNdwVFomW3QjH3

1 files changed, 0 insertions, 260 deletions

diff --git a/packages/meshbay-node/tests/test_audio_root_policy.py b/packages/meshbay-node/tests/test_audio_root_policy.py
deleted file mode 100644
index e2e9254..0000000
--- a/packages/meshbay-node/tests/test_audio_root_policy.py
+++ /dev/null
@@ -1,260 +0,0 @@
-"""
-Which folder (possibly a subfolder of a shared root) is the Music app's
-entry point for a group. Same shape as test_video_root_policy.py — a
-signed operator instruction, per-group, stored via roster.py's
-group_settings table, added later once a real messy library showed
-musicbay.md's original "no root, whole shared tree" call was wrong.
-"""
-
-import base64
-from pathlib import Path
-
-import pytest
-from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
-
-from meshbay_common.adminop import OP_AUDIO_ROOT, admin_transcript
-from meshbay_common.crypto import pk_to_b64
-from meshbay_common.join import ROLE_OPERATOR
-from meshbay_node.indexer.group_index import GroupIndex
-from meshbay_node.roster import Roster, open_roster
-from meshbay_node.transport.webrtc_server import WebRTCPeerSession
-
-from conftest import one_root
-
-pytestmark = pytest.mark.asyncio
-
-
-def _session(tmp_path: Path, user_id: str, *, operator: str | None = None) -> WebRTCPeerSession:
-    shared_root = tmp_path / "shared"
-    shared_root.mkdir(exist_ok=True)
-    (shared_root / "Music").mkdir()
-    (shared_root / "Podcasts").mkdir()
-    index = GroupIndex(group_id="g" * 32, sk_node=Ed25519PrivateKey.generate())
-    ctx = {
-        "roots": one_root(shared_root),
-        "index": index,
-        "sk_node": index.sk_node,
-        "node_user_id": operator,
-    }
-    session = WebRTCPeerSession.__new__(WebRTCPeerSession)
-    session._ctx = ctx
-    session._group_id = None
-    session._user_id = user_id
-    session._pk_user = ""
-    session.sent = []
-    session._send = session.sent.append
-    session._audit = lambda *a, **k: None
-    return session
-
-
-# ── Refused before a challenge is even issued ───────────────────────────────
-
-async def test_missing_path_is_refused(tmp_path):
-    session = _session(tmp_path, "op", operator="op")
-    session._has_admin_authority = lambda: True
-    issued = []
-    session._issue_admin_challenge = lambda op, subject: issued.append((op, subject))
-
-    session._do_audio_root({})
-
-    assert not issued
-    assert [m for m in session.sent if m.get("type") == "error"]
-
-
-async def test_a_nonexistent_folder_is_refused(tmp_path):
-    session = _session(tmp_path, "op", operator="op")
-    session._has_admin_authority = lambda: True
-    issued = []
-    session._issue_admin_challenge = lambda op, subject: issued.append((op, subject))
-
-    session._do_audio_root({"path": "shared/Nonexistent"})
-
-    assert not issued, "a mistyped path must be refused before a signature round trip"
-    assert [m for m in session.sent if m.get("type") == "error"]
-
-
-async def test_path_traversal_is_refused(tmp_path):
-    session = _session(tmp_path, "op", operator="op")
-    session._has_admin_authority = lambda: True
-    issued = []
-    session._issue_admin_challenge = lambda op, subject: issued.append((op, subject))
-
-    session._do_audio_root({"path": "../../etc"})
-
-    assert not issued
-    assert [m for m in session.sent if m.get("type") == "error"]
-
-
-async def test_a_request_with_nobody_to_authorize_it_is_refused(tmp_path):
-    session = _session(tmp_path, "member-1", operator="the-operator")
-    session._has_admin_authority = lambda: False
-
-    session._do_audio_root({"path": "shared/Music"})
-
-    assert [m for m in session.sent if m.get("type") == "error"]
-
-
-# ── Accepted cases ───────────────────────────────────────────────────────────
-
-async def test_an_empty_path_is_always_accepted(tmp_path):
-    """Empty means 'unset' — Music shows nothing yet, always valid to clear."""
-    session = _session(tmp_path, "op", operator="op")
-    session._has_admin_authority = lambda: True
-    issued = []
-    session._issue_admin_challenge = lambda op, subject: issued.append((op, subject))
-
-    session._do_audio_root({"path": ""})
-
-    assert issued == [(OP_AUDIO_ROOT, "")]
-
-
-async def test_a_real_subfolder_is_accepted_and_signed(tmp_path):
-    session = _session(tmp_path, "op", operator="op")
-    session._has_admin_authority = lambda: True
-    issued = []
-    session._issue_admin_challenge = lambda op, subject: issued.append((op, subject))
-
-    session._do_audio_root({"path": "shared/Music"})
-
-    assert issued == [(OP_AUDIO_ROOT, "shared/Music")]
-
-
-# ── Where it is stored ──────────────────────────────────────────────────────
-
-async def test_the_setting_lives_on_the_node_and_survives_a_restart(tmp_path):
-    roster = Roster(db_path=tmp_path / "roster.db")
-    await roster.open()
-    try:
-        assert await roster.app_directories("g1", "music") == [], (
-            "absent must mean unset")
-        await roster.set_app_directories("g1", "music", ["shared/Music"],
-                                         set_by="op")
-        assert await roster.app_directories("g1", "music") == ["shared/Music"]
-    finally:
-        await roster.close()
-
-    reopened = Roster(db_path=tmp_path / "roster.db")
-    await reopened.open()
-    try:
-        assert await reopened.app_directories("g1", "music") == ["shared/Music"]
-        assert await reopened.app_directories("g2", "music") == [], (
-            "one group's setting must not answer for another")
-    finally:
-        await reopened.close()
-
-
-# ── End to end through the real signed-op path ──────────────────────────────
-#
-# Everything above either calls ops.set_audio_root directly or mocks out
-# _issue_admin_challenge — neither one ever exercises real signature
-# verification (_verify_admin_sig, _do_admin_response) or the shared
-# groups_ctx/roster wiring _run_op depends on. Found live: a save that
-# looked like it worked (the Music tab showed content right afterward) did
-# not survive a reload — worth ruling out a break somewhere in that real
-# path specifically, not just in the pure-Python setter. Session shape
-# mirrors test_admin_ops_mnp.py's _session helper.
-
-GROUP = "g" * 32
-
-
-def _keypair():
-    sk = Ed25519PrivateKey.generate()
-    return sk, pk_to_b64(sk.public_key())
-
-
-async def _full_session(tmp_path: Path, roster) -> tuple[WebRTCPeerSession, Ed25519PrivateKey]:
-    shared = tmp_path / "shared"
-    (shared / "Music").mkdir(parents=True)
-    index = GroupIndex(group_id=GROUP, sk_node=Ed25519PrivateKey.generate())
-    roots = one_root(shared)
-
-    sk_op, pk_op = _keypair()
-    await roster.pin_identity("grenet", "grenet", pk_op, pk_op, "code")
-    await roster.set_member("", "grenet", ROLE_OPERATOR, "active", "local-cli")
-
-    group_ctx = {"gek": b"\x01" * 32, "roots": roots, "index": index,
-                 "join_policy": "invite", "audio_root": ""}
-    state = {
-        "groups_ctx": {GROUP: group_ctx},
-        "roster": roster,
-        "node_user_id": "node-user",
-    }
-
-    session = WebRTCPeerSession.__new__(WebRTCPeerSession)
-    session._ctx = {
-        "roots": roots, "index": index, "sk_node": index.sk_node,
-        "roster": roster, "groups": {GROUP: group_ctx},
-        "has_admin_authority": True,
-        "daemon_state": state,
-    }
-    session._group_id = GROUP
-    session._user_id = "grenet"
-    session._pk_user = ""
-    session._admin_ops = {}
-    session.sent = []
-    session._send = session.sent.append
-    session._audit = lambda *a, **k: None
-    session.spawned = []
-    session._spawn = session.spawned.append
-    # A real session registers itself here on handshake completion
-    # (`self._peer_registry()[self._user_id] = self`) — without it, the
-    # broadcast loop in _admin_exec_audio_root (and every other admin op)
-    # has nobody to send the final ack to, including the requester itself.
-    group_ctx["_peers"] = {"grenet": session}
-    session._peer_registry = lambda: group_ctx["_peers"]
-    return session, sk_op
-
-
-async def _drain(session):
-    for coro in session.spawned:
-        await coro
-    session.spawned.clear()
-
-
-async def test_a_real_signed_save_persists_and_survives_a_fresh_roster_read(tmp_path):
-    """
-    The exact question a "worked, then reverted after reload" report raises:
-    does the value set through the real challenge/response path actually
-    land in the database, in a form any later connection — this one, or a
-    freshly-opened Roster after a restart — reads back correctly?
-    """
-    roster = await open_roster(tmp_path)
-    try:
-        session, sk_op = await _full_session(tmp_path, roster)
-
-        session._do_audio_root({"path": "shared/Music"})
-        challenge = session.sent[-1]
-        assert challenge["type"] == "admin_challenge", challenge
-
-        transcript = admin_transcript(
-            op=OP_AUDIO_ROOT, node_pk_b64=session._node_pk_b64(), group_id=GROUP,
-            subject="shared/Music", nonce=base64.b64decode(challenge["nonce"]),
-            ts=challenge["ts"])
-        session._do_admin_response({
-            "op_id": challenge["op_id"],
-            "signature": base64.b64encode(sk_op.sign(transcript)).decode(),
-        })
-        await _drain(session)
-
-        ack = session.sent[-1]
-        assert ack["type"] == "audio_root_ack", ack
-        assert ack["path"] == "shared/Music"
-
-        assert session._ctx["groups"][GROUP]["audio_root"] == "shared/Music", (
-            "the live in-memory context must reflect the new root immediately")
-        assert await roster.app_directories(GROUP, "music") == ["shared/Music"], (
-            "the same Roster instance must read back what it just wrote")
-    finally:
-        await roster.close()
-
-    # A fresh connection (or a restarted daemon) never touches the Roster
-    # instance above at all — it opens its own. This is the check that
-    # actually answers "does it survive a reload".
-    reopened = await open_roster(tmp_path)
-    try:
-        assert await reopened.app_directories(GROUP, "music") == ["shared/Music"], (
-            "a freshly-opened Roster against the same db file must see the "
-            "committed value — anything else means the write was never "
-            "durable in the first place")
-    finally:
-        await reopened.close()