feat: add macos container backend scaffold

bot_bottle/backend/macos_container/enumerate.py

@@ -0,0 +1,37 @@
+"""Active-agent enumeration for the macOS Apple Container backend."""
+
+from __future__ import annotations
+
+import subprocess
+
+from ...bottle_state import read_metadata
+from .. import ActiveAgent
+
+_PREFIX = "bot-bottle-"
+
+
+def enumerate_active() -> list[ActiveAgent]:
+    result = subprocess.run(
+        ["container", "list", "--quiet"],
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+    if result.returncode != 0:
+        return []
+    out: list[ActiveAgent] = []
+    for name in sorted(line.strip() for line in result.stdout.splitlines()):
+        if not name.startswith(_PREFIX):
+            continue
+        slug = name[len(_PREFIX):]
+        metadata = read_metadata(slug)
+        out.append(ActiveAgent(
+            backend_name="macos-container",
+            slug=slug,
+            agent_name=metadata.agent_name if metadata else "?",
+            started_at=metadata.started_at if metadata else "",
+            services=(),
+            label=metadata.label if metadata else "",
+            color=metadata.color if metadata else "",
+        ))
+    return out