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

apps/admin_console/core/state.py

@@ -30,6 +30,8 @@ class ServerState:
         self.ipc_server: asyncio.Server | None = None
         self.ipc_serve_task: asyncio.Task | None = None
         self.ipc_port: int | None = None
+        self.port: int = 8000
+        self.host: str = "0.0.0.0"
         self.is_shutting_down: bool = False
 
         self.current_process: asyncio.subprocess.Process | None = None