feat(config): add showMemoryPid setting to toggle footer memory/PID display

## 实现要点
新增全局配置项 showMemoryPid，允许用户通过 /config 面板关闭底部状态栏的内存值和 PID 显示（默认开启，行为不变）。

## 变更要点
- src/utils/config.ts：新增 showMemoryPid?: boolean 类型声明 + GLOBAL_CONFIG_KEYS 注册
- src/components/PromptInput/PromptInputFooterLeftSide.tsx：新增 isMemoryPidEnabled() 函数，RSS/PID 渲染受配置控制
- src/components/Settings/Config.tsx：/config UI 面板注册配置项，含 logEvent 埋点
- packages/builtin-tools/src/tools/ConfigTool/supportedSettings.ts：SUPPORTED_SETTINGS 注册

packages/builtin-tools/src/tools/ConfigTool/supportedSettings.ts

@@ -131,6 +131,11 @@ export const SUPPORTED_SETTINGS: Record<string, SettingConfig> = {
       'How to spawn teammates: "tmux" for traditional tmux, "in-process" for same process, "auto" to choose automatically',
     options: TEAMMATE_MODES,
   },
+  showMemoryPid: {
+    source: 'global',
+    type: 'boolean',
+    description: 'Show memory usage and PID in the footer status bar',
+  },
   ...(process.env.USER_TYPE === 'ant'
     ? {
         classifierPermissionsEnabled: {

src/components/PromptInput/PromptInputFooterLeftSide.tsx

@@ -365,8 +365,8 @@ function ModeIndicator({
     ...(shouldShowPrStatus
       ? [<PrBadge key="pr-status" number={prStatus.number!} url={prStatus.url!} reviewState={prStatus.reviewState!} />]
       : []),
-    // RSS memory indicator — always visible
+    // RSS memory indicator — configurable via showMemoryPid
-    ...(rssState
+    ...(isMemoryPidEnabled() && rssState
       ? [
           <Text
             key="rss"
@@ -626,3 +626,7 @@ function getSpinnerHintParts(
 function isPrStatusEnabled(): boolean {
   return getGlobalConfig().prStatusFooterEnabled ?? true;
 }
+
+function isMemoryPidEnabled(): boolean {
+  return getGlobalConfig().showMemoryPid ?? true;
+}

src/components/Settings/Config.tsx

@@ -868,6 +868,28 @@ export function Config({
         });
       },
     },
+    {
+      id: 'showMemoryPid',
+      label: 'Show memory & PID in footer',
+      value: globalConfig.showMemoryPid ?? true,
+      type: 'boolean' as const,
+      onChange(enabled: boolean) {
+        saveGlobalConfig(current => {
+          if (current.showMemoryPid === enabled) return current;
+          return {
+            ...current,
+            showMemoryPid: enabled,
+          };
+        });
+        setGlobalConfig({
+          ...getGlobalConfig(),
+          showMemoryPid: enabled,
+        });
+        logEvent('tengu_show_memory_pid_setting_changed', {
+          enabled,
+        });
+      },
+    },
     {
       id: 'model',
       label: 'Model',

src/utils/config.ts

@@ -544,6 +544,9 @@ export type GlobalConfig = {
   // PR status footer configuration (feature-flagged via GrowthBook)
   prStatusFooterEnabled?: boolean // Show PR review status in footer (default: true)
 
+  // RSS memory + PID footer display
+  showMemoryPid?: boolean // Show memory usage and PID in footer (default: true)
+
   // Tmux live panel visibility (ant-only, toggled via Enter on tmux pill)
   tungstenPanelVisible?: boolean
 
@@ -673,6 +676,7 @@ export const GLOBAL_CONFIG_KEYS = [
   'copyOnSelect',
   'permissionExplainerEnabled',
   'prStatusFooterEnabled',
+  'showMemoryPid',
   'remoteControlAtStartup',
   'remoteDialogSeen',
 ] as const