修复: AI上下文邻接性收口 + 设置页i18n缺失键

- df-ai 三元组邻接性收口: sanitize/openai_compat 闭合判定由「id 全局存在」收紧为「紧后 tool 连续段覆盖」,夹层序列(后台压缩/用户插话楔入)不再直送 provider 致 400 insufficient tool messages
- 设置页补 settings.loading 缺失键(zh/en),修版本信息返回前渲染字面串
- 看板: 907 接手核查补注(实现口径=剥除非归位,有损)+ 遗留登记 909 + 908 销账

src/i18n/en/settings.ts

@@ -138,6 +138,7 @@ export default {
     sectionAbout: 'ℹ️ About DevFlow',
     labelAppVersion: 'Current version',
     descAppVersion: 'DevFlow desktop app version (injected at compile time, same source as the installer)',
+    loading: 'Loading…',
     labelCheckUpdate: 'Check for updates',
     descCheckUpdate: 'Fetch the latest version info from the release source; a new version prompts download & install (wired in B2)',
     checkUpdateAction: 'Check for updates',

src/i18n/zh-CN/settings.ts

@@ -137,6 +137,7 @@ export default {
     sectionAbout: 'ℹ️ 关于 DevFlow',
     labelAppVersion: '当前版本',
     descAppVersion: 'DevFlow 桌面应用版本号(编译期注入,与安装包同源)',
+    loading: '加载中…',
     labelCheckUpdate: '检查更新',
     descCheckUpdate: '从发布源拉取最新版本信息;有新版会提示下载安装(B2 接入)',
     checkUpdateAction: '检查更新',