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

backend/internal/service/account.go

@@ -1138,13 +1138,16 @@ func (a *Account) GetSessionIdleTimeoutMinutes() int {
 }
 
 // GetBaseRPM 获取基础 RPM 限制
-// 返回 0 表示未启用
+// 返回 0 表示未启用（负数视为无效配置，按 0 处理）
 func (a *Account) GetBaseRPM() int {
 	if a.Extra == nil {
 		return 0
 	}
 	if v, ok := a.Extra["base_rpm"]; ok {
-		return parseExtraInt(v)
+		val := parseExtraInt(v)
+		if val > 0 {
+			return val
+		}
 	}
 	return 0
 }

backend/internal/service/account_rpm_test.go

@@ -13,6 +13,9 @@ func TestGetBaseRPM(t *testing.T) {
 		{"zero", map[string]any{"base_rpm": 0}, 0},
 		{"int value", map[string]any{"base_rpm": 15}, 15},
 		{"float value", map[string]any{"base_rpm": 15.0}, 15},
+		{"string value", map[string]any{"base_rpm": "15"}, 15},
+		{"negative value", map[string]any{"base_rpm": -5}, 0},
+		{"int64 value", map[string]any{"base_rpm": int64(20)}, 20},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -35,6 +38,8 @@ func TestGetRPMStrategy(t *testing.T) {
 		{"tiered", map[string]any{"rpm_strategy": "tiered"}, "tiered"},
 		{"sticky_exempt", map[string]any{"rpm_strategy": "sticky_exempt"}, "sticky_exempt"},
 		{"invalid", map[string]any{"rpm_strategy": "foobar"}, "tiered"},
+		{"empty string fallback", map[string]any{"rpm_strategy": ""}, "tiered"},
+		{"numeric value fallback", map[string]any{"rpm_strategy": 123}, "tiered"},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -61,6 +66,13 @@ func TestCheckRPMSchedulability(t *testing.T) {
 		{"sticky_exempt over limit", map[string]any{"base_rpm": 15, "rpm_strategy": "sticky_exempt"}, 100, WindowCostStickyOnly},
 		{"custom buffer", map[string]any{"base_rpm": 10, "rpm_sticky_buffer": 5}, 14, WindowCostStickyOnly},
 		{"custom buffer red", map[string]any{"base_rpm": 10, "rpm_sticky_buffer": 5}, 15, WindowCostNotSchedulable},
+		{"base_rpm=1 green", map[string]any{"base_rpm": 1}, 0, WindowCostSchedulable},
+		{"base_rpm=1 yellow (at limit)", map[string]any{"base_rpm": 1}, 1, WindowCostStickyOnly},
+		{"base_rpm=1 red (at limit+buffer)", map[string]any{"base_rpm": 1}, 2, WindowCostNotSchedulable},
+		{"negative currentRPM", map[string]any{"base_rpm": 15}, -1, WindowCostSchedulable},
+		{"base_rpm negative disabled", map[string]any{"base_rpm": -5}, 10, WindowCostSchedulable},
+		{"very high currentRPM", map[string]any{"base_rpm": 10}, 9999, WindowCostNotSchedulable},
+		{"sticky_exempt very high currentRPM", map[string]any{"base_rpm": 10, "rpm_strategy": "sticky_exempt"}, 9999, WindowCostStickyOnly},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -71,3 +83,33 @@ func TestCheckRPMSchedulability(t *testing.T) {
 		})
 	}
 }
+
+func TestGetRPMStickyBuffer(t *testing.T) {
+	tests := []struct {
+		name     string
+		extra    map[string]any
+		expected int
+	}{
+		{"nil extra", nil, 0},
+		{"no keys", map[string]any{}, 0},
+		{"base_rpm=0", map[string]any{"base_rpm": 0}, 0},
+		{"base_rpm=1 min buffer 1", map[string]any{"base_rpm": 1}, 1},
+		{"base_rpm=4 min buffer 1", map[string]any{"base_rpm": 4}, 1},
+		{"base_rpm=5 buffer 1", map[string]any{"base_rpm": 5}, 1},
+		{"base_rpm=10 buffer 2", map[string]any{"base_rpm": 10}, 2},
+		{"base_rpm=15 buffer 3", map[string]any{"base_rpm": 15}, 3},
+		{"base_rpm=100 buffer 20", map[string]any{"base_rpm": 100}, 20},
+		{"custom buffer=5", map[string]any{"base_rpm": 10, "rpm_sticky_buffer": 5}, 5},
+		{"custom buffer=0 fallback to default", map[string]any{"base_rpm": 10, "rpm_sticky_buffer": 0}, 2},
+		{"custom buffer negative fallback", map[string]any{"base_rpm": 10, "rpm_sticky_buffer": -1}, 2},
+		{"custom buffer with float", map[string]any{"base_rpm": 10, "rpm_sticky_buffer": float64(7)}, 7},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			a := &Account{Extra: tt.extra}
+			if got := a.GetRPMStickyBuffer(); got != tt.expected {
+				t.Errorf("GetRPMStickyBuffer() = %d, want %d", got, tt.expected)
+			}
+		})
+	}
+}

backend/internal/service/gateway_service.go

@@ -2708,6 +2708,9 @@ func (s *GatewayService) selectAccountForModelWithPlatform(ctx context.Context,
 		}
 	}
 
+	// 批量预取 RPM 计数，避免逐个账号查询（N+1）
+	ctx = s.withRPMPrefetch(ctx, accounts)
+
 	// 3. 按优先级+最久未用选择（考虑模型支持）
 	var selected *Account
 	for i := range accounts {
@@ -2922,6 +2925,9 @@ func (s *GatewayService) selectAccountWithMixedScheduling(ctx context.Context, g
 		}
 	}
 
+	// 批量预取 RPM 计数，避免逐个账号查询（N+1）
+	ctx = s.withRPMPrefetch(ctx, accounts)
+
 	// 3. 按优先级+最久未用选择（考虑模型支持和混合调度）
 	var selected *Account
 	for i := range accounts {