feat: add multi-device concurrency, server lifecycle CLI, and unified execution stream

- Implement DevicePool and DeviceExecutionLock concurrency modes (per-device FIFO vs global serialization)
- Extend ArtemisClient SDK and CLI with explicit device targeting and concurrency strategy configuration
- Add server lifecycle management (artemis restart, stop, status) with cross-platform PID discovery
- Update MCP server tools to support multi-device dispatch, trace tagging, and per-device execution
- Enhance Showcase UI with step-by-step visual replay, playback speed controls, and device serial badges
- Add comprehensive unit test coverage and edge-case verification scripts

artemis/runtime/__init__.py

@@ -14,22 +14,57 @@
 
 """Artemis cross-platform runtime and process supervisor subsystem."""
 
-from artemis.runtime.device_lock import DeviceBusyError, DeviceExecutionLock
+from artemis.runtime.device_lock import (
+    ConcurrencyMode,
+    DeviceBusyError,
+    DeviceExecutionLock,
+)
+from artemis.runtime.device_pool import DevicePool, DeviceStatus, device_pool
+from artemis.runtime.daemon_client import (
+    ensure_daemon_running,
+    is_daemon_running,
+    submit_task_to_daemon,
+)
 from artemis.runtime.awake_service import (
     ensure_device_awake,
+    sanitize_device_state,
     screen_awake_service,
     shutdown_awake_service,
     start_awake_service,
 )
+from artemis.runtime.server_lifecycle import (
+    clear_server_info,
+    find_server_pids,
+    get_server_status,
+    is_port_in_use,
+    read_server_info,
+    stop_server,
+    write_server_info,
+)
 from artemis.runtime.supervisor import ProcessSupervisor, process_supervisor
 
 __all__ = [
+    "ConcurrencyMode",
     "DeviceBusyError",
     "DeviceExecutionLock",
+    "DevicePool",
+    "DeviceStatus",
+    "clear_server_info",
+    "device_pool",
+    "ensure_daemon_running",
     "ensure_device_awake",
+    "find_server_pids",
+    "get_server_status",
+    "is_daemon_running",
+    "is_port_in_use",
     "ProcessSupervisor",
     "process_supervisor",
+    "read_server_info",
+    "sanitize_device_state",
     "screen_awake_service",
     "shutdown_awake_service",
     "start_awake_service",
+    "stop_server",
+    "submit_task_to_daemon",
+    "write_server_info",
 ]