release: prepare Desktop and Agent 0.15.0

Align Desktop and Agent candidates at 0.15.0 and include the approved
Chinese and English release notes. Document Obsidian, conversation capture,
local native-client preview boundaries, and knowledge and Supervisor fixes.

Desktop upgrades storage to schema 48. Agent 0.15.0 requires Desktop 0.15.0;
remote telemetry opt-outs apply to newly started Runtimes. Keep the two
release channels independent and exclude the experimental LoongArch build.

Validation: 5317 tests passed, 79 skipped; typecheck, lint, and release-note
verification passed. Current-source Linux x64 OpenCode and Continue passed
Ask/Execute and telemetry-environment checks. Record preliminary probe
limitations and model-call accounting in the release preparation document.

Release note: Desktop 与 Agent 同步准备 0.15.0，新增 Obsidian、会话笔记采集及本地原生客户端预览，并修复知识库、监督者、界面与 Runtime 启动体验；升级前请备份完整用户数据，远程用户先升级桌面端再更新 Host。

agent-runtime-lock.json

@@ -1,6 +1,6 @@
 {
   "formatVersion": 1,
-  "agentVersion": "0.13.4",
+  "agentVersion": "0.15.0",
   "protocol": {
     "major": 2,
     "minor": 0