Fix get_mgr() to use ctx.lifespan_context (works in both request
and standalone Client mode). Add autouse fixture to reset
event-loop-bound singleton state per test, preventing cross-test
asyncio.Event contamination.
21 new tests exercise all 14 tools through FastMCP's in-memory
transport. New shortcuts: network_status (NetworkManager),
battery_status (UPower), bluetooth_devices (bluez),
kwin_windows (KRunner WindowsRunner). 53 tests pass.
Bridge Linux D-Bus IPC into MCP with tools for service discovery
(list_services, introspect, list_objects), method calls and property
access, plus convenience shortcuts for notifications, systemd units,
and MPRIS media player control. All 25 tests passing.
