feat(dsh-plugin): better-sidebar 集成、会话关停与归档清理、悬浮窗修复 (#130)

* better-sidebar 集成：observation 视图迁入 better-sidebar 载体，按会话作用域展示 bsk 会话
* 会话关停与归档清理：支持会话 dispose 与归档自动清理
* 悬浮窗修复：悬浮 overlay 拖拽/缩放/PiP 弹出等问题修复
* 修复 Document PiP 空白窗口：载体卸载（关 tab、切会话、插件 HMR）时主动 close() PiP 窗口，避免残留空白窗口

packages/dsh-plugin-browserskill/src/tools.ts

@@ -17,6 +17,7 @@ import {
   type ToolResult,
   type ToolRunContext,
 } from "@deepseek-ai/dsh-tools";
+import { ownerSessionIds } from "./archive-cleanup";
 import { trySaveScreenshot } from "./image";
 import { actionForLabel, type ObservationService } from "./observation";
 import type { KeyedExecutor } from "./queue";
@@ -245,6 +246,9 @@ export function registerTools(deps: ToolDeps): () => void {
           browserInstanceId: reply.browser_instance_id,
           startedAtMs: Date.now(),
         });
+        // Ownership for archive cleanup: the calling conversation and its
+        // ancestors reap this session when any of them is archived.
+        registry.trackOwner(reply.session_id, ownerSessionIds(deps.ctx, exec.agent?.id));
         deps.observation.addSession(reply.session_id, args.url);
         try {
           if (args.device !== undefined) {