clan-cli: use automatic networking for vars upload and machines update

This uses the networking module to find the best_host, as we already do
with ssh and install. So if we don't supply a --target-host and a
networking module is configured, the remote should be autodetected.

Since vars upload doesn't have a --target-host argument, we always try
to use get_best_remote

pkgs/clan-cli/clan_cli/machines/update.py

@@ -12,6 +12,7 @@ from clan_lib.machines.list import instantiate_inventory_to_machines
 from clan_lib.machines.machines import Machine
 from clan_lib.machines.suggestions import validate_machine_names
 from clan_lib.machines.update import run_machine_update
+from clan_lib.network.network import get_best_remote
 from clan_lib.nix import nix_config
 from clan_lib.ssh.host import Host
 from clan_lib.ssh.host_key import HostKeyCheck
@@ -27,6 +28,42 @@ from clan_cli.completions import (
 log = logging.getLogger(__name__)
 
 
+def run_update_with_network(
+    machine: Machine,
+    build_host: Remote | LocalHost | None,
+    upload_inputs: bool,
+    host_key_check: HostKeyCheck,
+    target_host_override: str | None = None,
+) -> None:
+    """Run machine update with proper network context handling.
+
+    If target_host_override is provided, use it directly.
+    Otherwise, use get_best_remote to establish network connection.
+    """
+    if target_host_override:
+        # Direct connection without network context
+        target_host = Remote.from_ssh_uri(
+            machine_name=machine.name,
+            address=target_host_override,
+        ).override(host_key_check=host_key_check)
+        run_machine_update(
+            machine=machine,
+            target_host=target_host,
+            build_host=build_host,
+            upload_inputs=upload_inputs,
+        )
+    else:
+        # Use network context
+        with get_best_remote(machine) as remote:
+            target_host = remote.override(host_key_check=host_key_check)
+            run_machine_update(
+                machine=machine,
+                target_host=target_host,
+                build_host=build_host,
+                upload_inputs=upload_inputs,
+            )
+
+
 def requires_explicit_update(m: Machine) -> bool:
     try:
         if m.select("config.clan.deployment.requireExplicitUpdate"):
@@ -144,27 +181,19 @@ def update_command(args: argparse.Namespace) -> None:
                         ).override(host_key_check=host_key_check)
                 else:
                     build_host = machine.build_host()
-                # Figure out the target host
-                if args.target_host:
-                    target_host = Remote.from_ssh_uri(
-                        machine_name=machine.name,
-                        address=args.target_host,
-                    ).override(host_key_check=host_key_check)
-                else:
-                    target_host = machine.target_host().override(
-                        host_key_check=host_key_check
-                    )
-                # run the update
+
+                # Schedule the update with network handling
                 runtime.async_run(
                     AsyncOpts(
                         tid=machine.name,
                         async_ctx=AsyncContext(prefix=machine.name),
                     ),
-                    run_machine_update,
+                    run_update_with_network,
                     machine=machine,
-                    target_host=target_host,
                     build_host=build_host,
                     upload_inputs=args.upload_inputs,
+                    host_key_check=host_key_check,
+                    target_host_override=args.target_host,
                 )
             runtime.join_all()
             runtime.check_all()

pkgs/clan-cli/clan_cli/vars/upload.py

@@ -5,6 +5,7 @@ from pathlib import Path
 from clan_cli.completions import add_dynamic_completer, complete_machines
 from clan_lib.flake import require_flake
 from clan_lib.machines.machines import Machine
+from clan_lib.network.network import get_best_remote
 from clan_lib.ssh.host import Host
 
 log = logging.getLogger(__name__)
@@ -32,7 +33,12 @@ def upload_command(args: argparse.Namespace) -> None:
         populate_secret_vars(machine, directory)
         return
 
-    with machine.target_host().host_connection() as host, host.become_root() as host:
+    # Use get_best_remote to handle networking
+    with (
+        get_best_remote(machine) as remote,
+        remote.host_connection() as host,
+        host.become_root() as host,
+    ):
         upload_secret_vars(machine, host)