feat: add guided exploration and share user-started MCP backend

artemis/runtime/queue_files.py

@@ -0,0 +1,23 @@
+"""Coordinate queue file reads and replacement across Windows processes/threads."""
+
+from functools import lru_cache
+from pathlib import Path
+
+from filelock import FileLock
+
+
+@lru_cache(maxsize=128)
+def _directory_lock(directory: Path) -> FileLock:
+    # One small OS-backed lock per queue directory, not one leftover file per
+    # task. FileLock releases the OS lock when its process exits.
+    return FileLock(directory / ".artemis-queue-io.lock", timeout=3)
+
+
+def queue_file_lock(path: Path):
+    """Hold only during file I/O, never across device operations or retry sleeps."""
+    return _directory_lock(path.parent.resolve()).acquire(poll_interval=0.005)
+
+
+def read_queue_text(path: Path) -> str:
+    with queue_file_lock(path):
+        return path.read_text(encoding="utf-8")