优化: 缓存命中字段解析与提示词前缀稳定化

- openai 兼容口径补解析嵌套 cached_tokens
- cache 显示区分无数据与真零,估算轮不渲染
- 轨迹展开折叠空过程记录行降噪
- token 统计行恒完整可见不截断
- openai_compat 纳入 system 稳定易变拆分
- 系统警示与主题标记改尾部注入不位移前缀
- 工具结果视图压缩按入库时刻冻结
- 会话内工具集冻结仅增不减
- anthropic 缓存补消息级断点,设置页加开关
- 补 intent 测试对 Agent domain 覆盖

src/views/Settings.vue

@@ -33,6 +33,24 @@
           @providers-changed="onProvidersChanged"
         />
 
+        <!-- AI Prompt 缓存总开关(KV df-ai-anthropic-cache,默认关;后端每请求读 settings,改后即时生效)
+             开:Anthropic 协议端点 system+历史段显式缓存断点;openai_compat 前缀稳定拆分(易变段挪消息流末尾) -->
+        <section v-if="activeCategory === 'ai-model'" class="panel">
+          <div class="panel-header">
+            <h2>{{ $t('settings.panelAnthropicCache') }}</h2>
+          </div>
+          <SettingRow :label="$t('settings.labelAnthropicCache')" :desc="$t('settings.descAnthropicCache')">
+            <label class="toggle">
+              <input
+                type="checkbox"
+                :checked="anthropicCache"
+                @change="anthropicCache = ($event.target as HTMLInputElement).checked"
+              />
+              <span class="toggle-slider"></span>
+            </label>
+          </SettingRow>
+        </section>
+
         <!-- 知识库:auto_extract/trigger_mode/embedding_* -->
         <KnowledgePanel
           v-else-if="activeCategory === 'knowledge'"
@@ -68,6 +86,7 @@ import { useConfirm } from '@/composables/useConfirm'
 import { useToast } from '@/composables/useToast'
 import ConfirmDialog from '@/components/ConfirmDialog.vue'
 import SettingsNav, { type SettingsCategory } from '@/components/settings/SettingsNav.vue'
+import SettingRow from '@/components/settings/SettingRow.vue'
 import ProviderPanel from '@/components/settings/ProviderPanel.vue'
 import ConnectionPanel from '@/components/settings/ConnectionPanel.vue'
 import AppearanceSection from '@/components/settings/AppearanceSection.vue'
@@ -108,6 +127,10 @@ const activeCategory = computed<SettingsCategory>({
   set: (v) => { void appSettings.set('df-settings-active-category', v) },
 })
 
+// AI Prompt 缓存总开关(KV df-ai-anthropic-cache,默认关,与后端 prompt.rs cache_enabled 同键;
+// 值落库为 JSON 布尔,后端 "true"/"1" 判定兼容)
+const anthropicCache = appSettings.useSetting<boolean>('df-ai-anthropic-cache', false)
+
 // 窄屏响应式:监听窗口宽度,nav 折叠为横向 tab(避免依赖仅 CSS 的 :has,
 // 并让 SettingsNav 按横向模式渲染 list)
 const isNarrowScreen = ref(false)