feat: extract in-process MCP action layer, concurrent task dispatch, and spawn/reconcile hardening

- Extract device action execution into artemis/mcp action layer:
  typed ActionResult, capability manifest with startup validation,
  AdbActuator as the single physical implementation, in-memory
  ActionSession (replaces stdio subprocess MCP in validator), and
  McpActionExecutor preserving the legacy executor contract.
  adb_server keeps its external stdio/SSE surface unchanged and now
  reuses the actuator implementation; import-time side effects moved
  into configure_stdio_mode().
- Capability-gated prompt assembly (prompt_assembly.py): tool enums and
  teaching segments render per available backend tools; full-set output
  is byte-identical to the previous static text (locked by tests).
- Admin console task queue: serial worker replaced by a per-device
  concurrent dispatcher (ARTEMIS_CONCURRENCY_MODE=global restores
  serial semantics), per-session cancellation, strict device binding on
  enqueue, unified stdio piping with tee to trace stdout.log, and
  shutdown cleanup of all active runs. Fix _pid_exists exception order
  so PermissionError is treated as alive.
- mcp_server reliability: spawn watchdog kills runners stuck before
  interpreter startup and releases device reservations; task state
  reconcile uses psutil liveness, prefers runner-reported pids, and
  adds a 45s startup grace to stop false failure reports on Windows;
  conversation_id is now optional end-to-end; explicit device_serial is
  validated at submission.
- CLI install now writes ~/.claude/rules/artemis.md for Claude Code and
  migrates/removes the legacy CLAUDE.md injection block; ~/.claude.json
  is never rewritten when it fails to parse.
- Tests: Windows-portable stdio lifecycle and path assertions; new
  suites for action layer, prompt assembly, spawn watchdog, and task
  reconcile (895 passed, 3 skipped).

mcp_server/background/task_runner.py

@@ -366,7 +366,11 @@ if __name__ == "__main__":
     parser.add_argument("--trace-id", required=True, help="Unique trace identifier")
     parser.add_argument("--task-desc", required=True, help="Description of the task to run")
     parser.add_argument("--model", required=True, help="Model to use ('Flash' or 'Pro')")
-    parser.add_argument("--conversation-id", required=True, help="Active conversation ID")
+    parser.add_argument(
+        "--conversation-id",
+        default="",
+        help="Conversation ID for wakeup notification routing (optional; empty disables routing)",
+    )
     parser.add_argument("--locked-app-package", help="Package name of app to lock execution to")
     parser.add_argument("--app-path", help="Path to local APK to install before running task")
     parser.add_argument("--expected-output-desc", help="Expected output description")