chore(release): 0.15.1 (#324)

* chore(release): 0.15.1

- bump version: package.json / dsh.plugin.json / SIDEBAR_SERVICE_VERSION
- README / README_EN: add v0.15.1 changelog (sidechat Codex-style transcript
  rework, terminal park-frame pty keep-alive, file-tree drag gating, README
  rewrite); plugin ecosystem 28+ with two new entries
  (dsh-better-sidebar-starter, my-dsh-plugins) and per-category <details>
  collapsible listings

* docs(readme): add community section placeholder for WeChat/QQ group QR codes

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dsh-better-sidebar",
-  "version": "0.15.0",
+  "version": "0.15.1",
   "description": "DSH web plugin: a VSCode-like right sidebar (explorer / editor / terminal / git / browser), isolated per conversation session. Exposes a service for other plugins to register sidebar tabs and file viewers.",
   "type": "module",
   "repository": {