release: prepare Desktop 0.15.5

Document incremental Smart heartbeat reviews, evidence-backed suggestions, interrupted-turn history, floating checklists, and note save behavior. Record schema 50 backup requirements and real Host cancellation validation; Agent remains 0.15.1.

Release note: 智能心跳按变化回顾并提供有依据的建议，修复取消后续聊、清单展开和笔记保存体验；升级前请备份数据库及笔记。

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "goodbuddy",
-  "version": "0.15.4",
+  "version": "0.15.5",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "goodbuddy",
-      "version": "0.15.4",
+      "version": "0.15.5",
       "license": "0BSD",
       "dependencies": {
         "@agentclientprotocol/sdk": "0.25.1",