Filter /-/databases by view-database permission

/-/databases previously listed every attached database (including
filesystem paths and sizes) to any actor with view-instance, while the
homepage and every other endpoint filtered by view-database. The
endpoint now only lists databases the current actor is allowed to view.

JsonDataView data callbacks may now be async.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GrHZSypDfMnym1tM5XJAFZ

tests/test_permissions.py

@@ -1800,3 +1800,35 @@ async def test_root_allow_block_with_table_restricted_actor():
         actor=admin_actor,
     )
     assert result is True
+
+
+@pytest.mark.asyncio
+async def test_databases_json_respects_view_database(tmp_path_factory):
+    # https://github.com/simonw/datasette - /-/databases should not list
+    # databases the actor is not allowed to view
+    db_directory = tmp_path_factory.mktemp("dbs")
+    from datasette.utils import sqlite3 as _sqlite3
+
+    paths = []
+    for name in ("public", "private"):
+        path = str(db_directory / "{}.db".format(name))
+        conn = _sqlite3.connect(path)
+        conn.execute("vacuum")
+        conn.close()
+        paths.append(path)
+    ds = Datasette(
+        paths,
+        config={"databases": {"private": {"allow": {"id": "root"}}}},
+    )
+    ds.root_enabled = True
+    await ds.invoke_startup()
+    try:
+        anon_response = await ds.client.get("/-/databases.json")
+        assert anon_response.status_code == 200
+        anon_names = {db["name"] for db in anon_response.json()["databases"]}
+        assert anon_names == {"public"}
+        root_response = await ds.client.get("/-/databases.json", actor={"id": "root"})
+        root_names = {db["name"] for db in root_response.json()["databases"]}
+        assert root_names == {"public", "private"}
+    finally:
+        ds.close()