## ADDED Requirements

### Requirement: IoT Card Batch Series Binding Range Allocation Hint

The IoT card batch series binding dialog SHALL provide a derived allocation-count hint for ICCID range selection.

The hint MUST appear immediately below the `iccid_start` and `iccid_end` inputs.

The count MUST be computed with exact integer arithmetic as `iccid_end - iccid_start + 1` so that long ICCID values do not lose precision.

#### Scenario: Show allocation count for a valid ICCID range

- **GIVEN** 用户打开“批量设置套餐系列绑定”弹窗
- **AND** 用户选择 `selection_type="range"`
- **WHEN** 用户输入 `iccid_start` 和 `iccid_end`，且计算结果为正整数
- **THEN** 弹窗 MUST 显示 `共分配xxx张卡`
- **AND** `xxx` MUST 等于 `iccid_end - iccid_start + 1`
- **AND** 当任一端点变化时，提示 MUST 立即更新

#### Scenario: Hide count hint for incomplete or invalid ICCID ranges

- **GIVEN** 用户选择 `selection_type="range"`
- **WHEN** 任一起止 ICCID 为空、无法按整数计算，或计算结果小于 `1`
- **THEN** 弹窗 MUST NOT 显示误导性的分配数量提示