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/api.py

@@ -86,6 +86,7 @@ class Pyro:
         ttl_seconds: int = DEFAULT_TTL_SECONDS,
         network: bool = False,
         allow_host_compat: bool = DEFAULT_ALLOW_HOST_COMPAT,
+        source_path: str | Path | None = None,
     ) -> dict[str, Any]:
         return self._manager.create_task(
             environment=environment,
@@ -94,6 +95,7 @@ class Pyro:
             ttl_seconds=ttl_seconds,
             network=network,
             allow_host_compat=allow_host_compat,
+            source_path=source_path,
         )
 
     def exec_task(
@@ -245,6 +247,7 @@ class Pyro:
             ttl_seconds: int = DEFAULT_TTL_SECONDS,
             network: bool = False,
             allow_host_compat: bool = DEFAULT_ALLOW_HOST_COMPAT,
+            source_path: str | None = None,
         ) -> dict[str, Any]:
             """Create and start a persistent task workspace."""
             return self.create_task(
@@ -254,6 +257,7 @@ class Pyro:
                 ttl_seconds=ttl_seconds,
                 network=network,
                 allow_host_compat=allow_host_compat,
+                source_path=source_path,
             )
 
         @server.tool()