chore: release v0.4.3 — README 精简重排 + npm 启动模式实测兼容

- README 341 → 130 行：安装/更新合并为一份提示词 + 手动要点，功能一览
  逐节压缩，registry 通道降为可选小节，开发/架构/限制精简；新增
  「npm 包启动（npx @deepseek-ai/dsh）同样可用，v0.4.3 起实测验证」
- 版本 0.4.1 → 0.4.3；cordis.patch.yml 注释同步

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dsh-better-sidebar",
-  "version": "0.4.1",
+  "version": "0.4.3",
   "description": "DSH web plugin: a VSCode-like right sidebar (explorer / editor / terminal / git), isolated per conversation session. Exposes a service for other plugins to register sidebar tabs and file viewers.",
   "private": true,
   "type": "module",