fix(smolmachines): stop VM before pack commit, with confirm prompt

smolvm pack create --from-vm requires the VM to be stopped. Add
machine_is_running() to smolvm.py (via machine ls --json state field),
and add the same confirm-stop flow to SmolmachinesFreezer that was
originally designed for macos-container: if running, prompt the user,
stop the VM, then pack. Already-stopped VMs are packed directly.

bot_bottle/backend/smolmachines/freezer.py

@@ -2,15 +2,31 @@
 
 from __future__ import annotations
 
+import sys
+
 from .. import ActiveAgent
-from ..freeze import Freezer
-from .smolvm import pack_create_from_vm
+from ..freeze import CommitCancelled, Freezer
+from .smolvm import machine_is_running, machine_stop, pack_create_from_vm
 from ...bottle_state import bottle_state_dir
 from ...log import info
 
 
+def _read_tty_line() -> str:
+    """Read one line from /dev/tty, falling back to stdin."""
+    try:
+        with open("/dev/tty", "r", encoding="utf-8") as tty:
+            return tty.readline().rstrip("\n")
+    except OSError:
+        return sys.stdin.readline().rstrip("\n")
+
+
 class SmolmachinesFreezer(Freezer):
-    """Freezes a smolmachines bottle via `smolvm pack create --from-vm`."""
+    """Freezes a smolmachines bottle via `smolvm pack create --from-vm`.
+
+    `smolvm pack create --from-vm` requires the VM to be stopped first.
+    If the VM is running the freezer prompts the user to confirm the stop
+    before proceeding. The VM remains stopped after commit; use
+    `./cli.py resume` to restart."""
 
     backend_name = "smolmachines"
 
@@ -18,6 +34,16 @@ class SmolmachinesFreezer(Freezer):
         machine = f"bot-bottle-{agent.slug}"
         output = bottle_state_dir(agent.slug) / "committed-smolmachine"
         output.parent.mkdir(parents=True, exist_ok=True)
+        if machine_is_running(machine):
+            sys.stderr.write(
+                f"bot-bottle: bottle {agent.slug!r} is running; "
+                "commit will stop it. Continue? [y/N] "
+            )
+            sys.stderr.flush()
+            reply = _read_tty_line().strip().lower()
+            if reply not in ("y", "yes"):
+                raise CommitCancelled
+            machine_stop(machine)
         pack_create_from_vm(machine, output)
         artifact = output.with_name(f"{output.name}.smolmachine")
         return str(artifact)

bot_bottle/backend/smolmachines/smolvm.py

@@ -25,6 +25,7 @@ smolvm binary."""
 
 from __future__ import annotations
 
+import json
 import shutil
 import subprocess
 import time
@@ -153,6 +154,21 @@ def machine_create(
     _smolvm(*args)
 
 
+def machine_is_running(name: str) -> bool:
+    """Return True if the named VM is in the 'running' state."""
+    result = _smolvm("machine", "ls", "--json", check=False)
+    if result.returncode != 0:
+        return False
+    try:
+        machines = json.loads(result.stdout or "[]")
+    except ValueError:
+        return False
+    return any(
+        isinstance(m, dict) and m.get("name") == name and m.get("state") == "running"
+        for m in machines
+    )
+
+
 def machine_start(name: str) -> None:
     """`smolvm machine start --name NAME`."""
     _smolvm("machine", "start", "--name", name)