refactor(bottles): move 'list active' onto DockerBottlePlatform

Add list_active() abstract method on BottlePlatform; DockerBottlePlatform
implements it with the existing docker ps logic. cli/list.py no longer
calls docker directly — it just dispatches the active branch to the
platform.

claude_bottle/bottles/__init__.py

@@ -122,6 +122,11 @@ class BottlePlatform(ABC):
     def cleanup(self, plan: BottleCleanupPlan) -> None:
         """Remove everything described by the cleanup plan."""
 
+    @abstractmethod
+    def list_active(self) -> None:
+        """Print every currently-running bottle on this platform to
+        stderr (name + status)."""
+
 
 # Import concrete platform classes AFTER the base types are defined, so
 # each platform module can pull BottleSpec / BottlePlan / BottlePlatform

claude_bottle/bottles/docker.py

@@ -527,3 +527,28 @@ class DockerBottlePlatform(BottlePlatform):
                 stdout=subprocess.DEVNULL,
                 stderr=subprocess.DEVNULL,
             )
+
+    # --- List ---
+
+    def list_active(self) -> None:
+        """Print all running claude-bottle containers (name + status).
+        Prints a single-line banner if there are none."""
+        docker_mod.require_docker()
+        result = subprocess.run(
+            [
+                "docker", "ps",
+                "--filter", "name=^claude-bottle-",
+                "--format", "{{.Names}}\t{{.Status}}",
+            ],
+            capture_output=True,
+            text=True,
+        )
+        containers = (result.stdout or "").strip()
+        if not containers:
+            info("no active claude-bottle containers")
+            return
+        print()
+        for line in containers.splitlines():
+            name, _, status = line.partition("\t")
+            info(f"container: {name}  status: {status}")
+        print()

claude_bottle/cli/list.py

@@ -1,12 +1,10 @@
-"""list: list available agents or active containers."""
+"""list: list available agents or active bottles."""
 
 from __future__ import annotations
 
 import argparse
-import subprocess
 
-from .. import docker as docker_mod
-from ..log import info
+from ..bottles import get_bottle_platform
 from ..manifest import Manifest
 from ._common import PROG, USER_CWD
 
@@ -22,23 +20,5 @@ def cmd_list(argv: list[str]) -> int:
             print(name)
         return 0
 
-    docker_mod.require_docker()
-    result = subprocess.run(
-        [
-            "docker", "ps",
-            "--filter", "name=^claude-bottle-",
-            "--format", "{{.Names}}\t{{.Status}}",
-        ],
-        capture_output=True,
-        text=True,
-    )
-    containers = (result.stdout or "").strip()
-    if not containers:
-        info("no active claude-bottle containers")
-        return 0
-    print()
-    for line in containers.splitlines():
-        name, _, status = line.partition("\t")
-        info(f"container: {name}  status: {status}")
-    print()
+    get_bottle_platform().list_active()
     return 0