refactor(docker): split backend.py into prepare / launch / cleanup

Move the resolution, bring-up, and orphan-cleanup logic out of
backend.py into three topic-named modules. DockerBottleBackend becomes
a thin façade that wires the per-instance pipelock proxy and the
provision orchestrator into the free functions.

backend.py drops from ~360 to ~70 lines and each topic now reads
end-to-end in one place. Mirrors the existing provision/ split.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

claude_bottle/backend/docker/cleanup.py

@@ -0,0 +1,104 @@
+"""Cleanup + active-listing for the Docker bottle backend.
+
+`prepare_cleanup` enumerates orphaned `claude-bottle-` containers and
+networks; `cleanup` removes them. `list_active` queries the same
+namespace for ad-hoc inspection. All three share a single concern:
+acting on resources whose names start with `claude-bottle-`.
+"""
+
+from __future__ import annotations
+
+import subprocess
+
+from ...log import info
+from . import util as docker_mod
+from .bottle_cleanup_plan import DockerBottleCleanupPlan
+
+
+def prepare_cleanup() -> DockerBottleCleanupPlan:
+    """Enumerate all claude-bottle-prefixed containers (running or
+    stopped) and networks. No removals — caller confirms first."""
+    docker_mod.require_docker()
+
+    # `docker ps -a --filter name=...` uses regex matching; anchor at
+    # the start so we don't pick up containers that merely contain
+    # "claude-bottle-" mid-name.
+    cr = subprocess.run(
+        [
+            "docker", "ps", "-a",
+            "--filter", "name=^claude-bottle-",
+            "--format", "{{.Names}}",
+        ],
+        capture_output=True,
+        text=True,
+        check=True,
+    )
+    containers = tuple(sorted(
+        line for line in (cr.stdout or "").splitlines() if line
+    ))
+
+    # `docker network ls --filter name=...` uses substring matching.
+    # "claude-bottle-" is specific enough that false positives are
+    # not a concern.
+    nr = subprocess.run(
+        [
+            "docker", "network", "ls",
+            "--filter", "name=claude-bottle-",
+            "--format", "{{.Name}}",
+        ],
+        capture_output=True,
+        text=True,
+        check=True,
+    )
+    networks = tuple(sorted(
+        line for line in (nr.stdout or "").splitlines() if line
+    ))
+
+    return DockerBottleCleanupPlan(containers=containers, networks=networks)
+
+
+def cleanup(plan: DockerBottleCleanupPlan) -> None:
+    """Remove the containers and networks listed in the plan.
+    Containers first; networks would refuse to delete while containers
+    are still attached."""
+    for name in plan.containers:
+        info(f"removing container {name}")
+        subprocess.run(
+            ["docker", "rm", "-f", name],
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            check=False,
+        )
+    for name in plan.networks:
+        info(f"removing network {name}")
+        subprocess.run(
+            ["docker", "network", "rm", name],
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            check=False,
+        )
+
+
+def list_active() -> 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,
+        check=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()