feat(settings): 适配 kimi-code 0.42.0 —— 实验 flag 镜像 9→6

- 删除已转正/移除的 4 个 flag：secondary-model（模型池恒开）、
  persistence_minidb_readmodel（改由 [database] 配置节）、remote-control、
  search_worker；env 探测清单同步 11→8
- 新增 notify_user flag（KIMI_CODE_EXPERIMENTAL_NOTIFY_USER，实验性
  Updates 面板，默认关闭）
- 设置页移除 secondary-model 专属卡片与「默认开启」徽章，6 个 flag 统一渲染；
  [secondary_model] 模型池配置逻辑不变
- 残留旧键上游 schema 宽容忽略，无需迁移

src/i18n/en.ts

@@ -463,15 +463,10 @@ export const enTranslations: Record<TranslationKey, string> = {
   // Advanced settings page (WebUI quick open + experimental flags + secondary model)
   subagentSettings: "Advanced Settings",
   experimentalFlags: "Experimental Features",
-  otherExperimentalFlags: "Other Experimental Features",
   experimentalFlagsHint:
     "Toggles are written to the [experimental] section of config.toml; env vars take precedence and locked toggles cannot be changed here",
-  flagSecondaryModel: "Subagent Secondary Model",
-  flagSecondaryModelDesc: "Newly spawned subagents bind a second (usually cheaper) model config",
   flagToolSelect: "Tool Select",
   flagToolSelectDesc: "Enable the experimental tool selection feature",
-  flagMinidbReadmodel: "MiniDB Read Model",
-  flagMinidbReadmodelDesc: "Enable the v2 engine MiniDB read-model backend",
   flagTower: "Tower Mode",
   flagTowerDesc: "Enable tower mode: coordinate multiple agents on a shared objective (/tower command)",
   flagSubagentFork: "Subagent Fork Context",
@@ -480,17 +475,13 @@ export const enTranslations: Record<TranslationKey, string> = {
   flagWaitForDesc: "The agent can wait for background tasks to finish within the current turn",
   flagAutoSessionTitle: "Auto Session Title",
   flagAutoSessionTitleDesc: "Generate session titles automatically via the managed chat_title tool",
-  flagRemoteControl: "Remote Control",
-  flagRemoteControlDesc: "Enable the experimental remote control feature",
-  flagSearchWorker: "Search Worker",
-  flagSearchWorkerDesc: "Run the kap-server global search backend in a background worker host",
+  flagNotifyUser: "NotifyUser tool",
+  flagNotifyUserDesc: "Experimental Updates panel: paginated progress messages from the main agent and subagents (off by default)",
   flagDefaultOn: "On by default",
   lockedByEnv: "Locked by env var",
   masterEnvOnHint:
     "KIMI_CODE_EXPERIMENTAL_FLAG is set: flags without an explicit [experimental] entry are forced on; explicit entries in config.toml still win",
   secondaryModelSection: "Subagent Model (Secondary Model)",
-  secondaryModelDisabledHint:
-    "The experimental flag \"Subagent Secondary Model\" is off and this config will not take effect — enable the toggle above first",
   secondaryModelLabel: "Secondary model",
   secondaryModelUnset: "Not configured",
   secondaryModelInheritedContext: "Inherited context",