Add seeded task workspace creation

Current persistent tasks started with an empty workspace, which blocked the first useful host-to-task workflow in the task roadmap. This change lets task creation start from a host directory or tar archive without changing the one-shot VM surfaces.

Expose source_path on task create across the CLI, SDK, and MCP, add safe archive upload and extraction support for guest and host-compat backends, persist workspace_seed metadata, and patch the per-task rootfs with the bundled guest agent before boot so seeded guest tasks work without republishing environments. Also switch post--- command reconstruction to shlex.join() so documented sh -lc task examples preserve argument boundaries.

Validation:
- uv lock
- UV_CACHE_DIR=.uv-cache uv run pytest --no-cov tests/test_vm_guest.py tests/test_vm_manager.py tests/test_cli.py tests/test_api.py tests/test_server.py tests/test_public_contract.py
- UV_CACHE_DIR=.uv-cache make check
- UV_CACHE_DIR=.uv-cache make dist-check
- real guest-backed smoke: task create --source-path, task exec -- cat note.txt, task delete

src/pyro_mcp/contract.py

@@ -6,6 +6,15 @@ PUBLIC_CLI_COMMANDS = ("demo", "doctor", "env", "mcp", "run", "task")
 PUBLIC_CLI_DEMO_SUBCOMMANDS = ("ollama",)
 PUBLIC_CLI_ENV_SUBCOMMANDS = ("inspect", "list", "pull", "prune")
 PUBLIC_CLI_TASK_SUBCOMMANDS = ("create", "delete", "exec", "logs", "status")
+PUBLIC_CLI_TASK_CREATE_FLAGS = (
+    "--vcpu-count",
+    "--mem-mib",
+    "--ttl-seconds",
+    "--network",
+    "--allow-host-compat",
+    "--source-path",
+    "--json",
+)
 PUBLIC_CLI_RUN_FLAGS = (
     "--vcpu-count",
     "--mem-mib",