fix: address code review issues for RPM limiting feature

- Use TxPipeline (MULTI/EXEC) instead of Pipeline for atomic INCR+EXPIRE
- Filter negative values in GetBaseRPM(), update test expectation
- Add RPM batch query (GetRPMBatch) to account List API
- Add warn logs for RPM increment failures in gateway handler
- Reset enableRpmLimit on BulkEditAccountModal close
- Use union type 'tiered' | 'sticky_exempt' for rpmStrategy refs
- Add design decision comments for rdb.Time() RTT trade-off

frontend/src/components/account/AccountCapacityCell.vue

@@ -68,6 +68,7 @@
         <span class="font-mono">{{ currentRPM }}</span>
         <span class="text-gray-400 dark:text-gray-500">/</span>
         <span class="font-mono">{{ account.base_rpm }}</span>
+        <span class="text-[9px] opacity-60">{{ rpmStrategyTag }}</span>
       </span>
     </div>
   </div>
@@ -143,19 +144,15 @@ const windowCostClass = computed(() => {
   const limit = props.account.window_cost_limit || 0
   const reserve = props.account.window_cost_sticky_reserve || 10
 
-  // >= 阈值+预留: 完全不可调度 (红色)
   if (current >= limit + reserve) {
     return 'bg-red-100 text-red-700 dark:bg-red-900/30 dark:text-red-400'
   }
-  // >= 阈值: 仅粘性会话 (橙色)
   if (current >= limit) {
     return 'bg-orange-100 text-orange-700 dark:bg-orange-900/30 dark:text-orange-400'
   }
-  // >= 80% 阈值: 警告 (黄色)
   if (current >= limit * 0.8) {
     return 'bg-yellow-100 text-yellow-700 dark:bg-yellow-900/30 dark:text-yellow-400'
   }
-  // 正常 (绿色)
   return 'bg-emerald-100 text-emerald-700 dark:bg-emerald-900/30 dark:text-emerald-400'
 })
 
@@ -183,15 +180,12 @@ const sessionLimitClass = computed(() => {
   const current = activeSessions.value
   const max = props.account.max_sessions || 0
 
-  // >= 最大: 完全占满 (红色)
   if (current >= max) {
     return 'bg-red-100 text-red-700 dark:bg-red-900/30 dark:text-red-400'
   }
-  // >= 80%: 警告 (黄色)
   if (current >= max * 0.8) {
     return 'bg-yellow-100 text-yellow-700 dark:bg-yellow-900/30 dark:text-yellow-400'
   }
-  // 正常 (绿色)
   return 'bg-emerald-100 text-emerald-700 dark:bg-emerald-900/30 dark:text-emerald-400'
 })
 
@@ -222,35 +216,74 @@ const showRpmLimit = computed(() => {
 // 当前 RPM 计数
 const currentRPM = computed(() => props.account.current_rpm ?? 0)
 
+// RPM 策略
+const rpmStrategy = computed(() => props.account.rpm_strategy || 'tiered')
+
+// RPM 策略标签
+const rpmStrategyTag = computed(() => {
+  return rpmStrategy.value === 'sticky_exempt' ? '[S]' : '[T]'
+})
+
+// RPM buffer 计算（与后端一致：base <= 0 时 buffer 为 0）
+const rpmBuffer = computed(() => {
+  const base = props.account.base_rpm || 0
+  return props.account.rpm_sticky_buffer ?? (base > 0 ? Math.max(1, Math.floor(base / 5)) : 0)
+})
+
 // RPM 状态样式
 const rpmClass = computed(() => {
   if (!showRpmLimit.value) return ''
 
   const current = currentRPM.value
   const base = props.account.base_rpm ?? 0
-  if (base <= 0) return 'bg-gray-100 text-gray-600 dark:bg-gray-700 dark:text-gray-400'
+  const buffer = rpmBuffer.value
 
-  const strategy = props.account.rpm_strategy || 'tiered'
-  if (strategy === 'tiered') {
-    const buffer = props.account.rpm_sticky_buffer ?? Math.max(1, Math.floor(base / 5))
-    if (current >= base + buffer) return 'bg-red-100 text-red-700 dark:bg-red-900/30 dark:text-red-400'
-    if (current >= base) return 'bg-orange-100 text-orange-700 dark:bg-orange-900/30 dark:text-orange-400'
+  if (rpmStrategy.value === 'tiered') {
+    if (current >= base + buffer) {
+      return 'bg-red-100 text-red-700 dark:bg-red-900/30 dark:text-red-400'
+    }
+    if (current >= base) {
+      return 'bg-orange-100 text-orange-700 dark:bg-orange-900/30 dark:text-orange-400'
+    }
   } else {
-    if (current >= base) return 'bg-orange-100 text-orange-700 dark:bg-orange-900/30 dark:text-orange-400'
+    if (current >= base) {
+      return 'bg-orange-100 text-orange-700 dark:bg-orange-900/30 dark:text-orange-400'
+    }
+  }
+  if (current >= base * 0.8) {
+    return 'bg-yellow-100 text-yellow-700 dark:bg-yellow-900/30 dark:text-yellow-400'
   }
-  if (current >= base * 0.8) return 'bg-yellow-100 text-yellow-700 dark:bg-yellow-900/30 dark:text-yellow-400'
   return 'bg-emerald-100 text-emerald-700 dark:bg-emerald-900/30 dark:text-emerald-400'
 })
 
-// RPM 提示文字
+// RPM 提示文字（增强版：显示策略、区域、缓冲区）
 const rpmTooltip = computed(() => {
   if (!showRpmLimit.value) return ''
 
   const current = currentRPM.value
   const base = props.account.base_rpm ?? 0
-  if (current >= base) return t('admin.accounts.capacity.rpm.full')
-  if (current >= base * 0.8) return t('admin.accounts.capacity.rpm.warning')
-  return t('admin.accounts.capacity.rpm.normal')
+  const buffer = rpmBuffer.value
+
+  if (rpmStrategy.value === 'tiered') {
+    if (current >= base + buffer) {
+      return t('admin.accounts.capacity.rpm.tieredBlocked', { buffer })
+    }
+    if (current >= base) {
+      return t('admin.accounts.capacity.rpm.tieredStickyOnly', { buffer })
+    }
+    if (current >= base * 0.8) {
+      return t('admin.accounts.capacity.rpm.tieredWarning')
+    }
+    return t('admin.accounts.capacity.rpm.tieredNormal')
+  } else {
+    if (current >= base) {
+      return t('admin.accounts.capacity.rpm.stickyExemptOver')
+    }
+    if (current >= base * 0.8) {
+      return t('admin.accounts.capacity.rpm.stickyExemptWarning')
+    }
+    return t('admin.accounts.capacity.rpm.stickyExemptNormal')
+  }
 })
 
 // 格式化费用显示