feat: add plugin disable and enable commands

src/plugin_helper/installer.py

@@ -77,6 +77,7 @@ def apply_plan(plan: dict[str, Any], state_root: Path) -> dict[str, Any]:
                 "size": target.stat().st_size,
             }
         )
+        installed_state.setdefault("disabledPlugins", {}).pop(change["plugin"], None)
         applied.append({"path": rel_target, "plugin": change["plugin"], "backup": backup})
 
     save_installed_state(state_root, instance, installed_state)
@@ -110,3 +111,37 @@ def uninstall_plugin(instance: str, instance_path: Path, state_root: Path, plugi
     installed_state.get("plugins", {}).pop(plugin_id, None)
     save_installed_state(state_root, instance, installed_state)
     return {"removed": removed, "skipped": skipped, "stateUpdated": True}
+
+
+def disable_plugin(instance: str, instance_path: Path, state_root: Path, plugin_id: str, force: bool = False) -> dict[str, Any]:
+    installed_state = load_installed_state(state_root, instance)
+    plugin_state = installed_state.get("plugins", {}).get(plugin_id)
+    if not plugin_state:
+        if plugin_id in installed_state.get("disabledPlugins", {}):
+            raise KeyError(f"plugin is already disabled: {plugin_id}")
+        raise KeyError(f"plugin is not recorded in install state: {plugin_id}")
+
+    removed: list[str] = []
+    skipped: list[dict[str, str]] = []
+    for item in plugin_state.get("files", []):
+        rel_path = ensure_relative(item["path"]).as_posix()
+        target = ensure_inside(instance_path, instance_path / rel_path)
+        if not target.exists():
+            removed.append(rel_path)
+            continue
+        current_sha = sha256_file(target)
+        if current_sha != item.get("sha256") and not force:
+            skipped.append({"path": rel_path, "reason": "hash mismatch"})
+            continue
+        target.unlink()
+        removed.append(rel_path)
+
+    if skipped and not force:
+        return {"removed": removed, "skipped": skipped, "stateUpdated": False}
+
+    disabled_state = dict(plugin_state)
+    disabled_state["disabledAt"] = datetime.now(timezone.utc).isoformat().replace("+00:00", "Z")
+    installed_state.setdefault("disabledPlugins", {})[plugin_id] = disabled_state
+    installed_state.get("plugins", {}).pop(plugin_id, None)
+    save_installed_state(state_root, instance, installed_state)
+    return {"removed": removed, "skipped": skipped, "stateUpdated": True}