Add persistent task workspace alpha

Start the first workspace milestone toward the task-oriented product without changing the existing one-shot vm_run/pyro run contract.

Add a disk-backed task registry in the manager, auto-started task workspaces rooted at /workspace, repeated non-cleaning exec, and persisted command journals exposed through task create/exec/status/logs/delete across the CLI, Python SDK, and MCP server.

Update the public contract, docs, examples, and version/catalog metadata for 2.1.0, and cover the new surface with manager, CLI, SDK, and MCP tests. Validation: UV_CACHE_DIR=.uv-cache make check and UV_CACHE_DIR=.uv-cache make dist-check.

examples/python_task.py

@@ -0,0 +1,21 @@
+from __future__ import annotations
+
+from pyro_mcp import Pyro
+
+
+def main() -> None:
+    pyro = Pyro()
+    created = pyro.create_task(environment="debian:12")
+    task_id = str(created["task_id"])
+    try:
+        pyro.exec_task(task_id, command="printf 'hello from task\\n' > note.txt")
+        result = pyro.exec_task(task_id, command="cat note.txt")
+        print(result["stdout"], end="")
+        logs = pyro.logs_task(task_id)
+        print(f"task_id={task_id} command_count={logs['count']}")
+    finally:
+        pyro.delete_task(task_id)
+
+
+if __name__ == "__main__":
+    main()