Function calculateAverageQuality

calculateAverageQuality(quality: string, encoding?: QualityEncoding): number
Calculate average quality score from a quality string

Optimized for streaming with single-pass calculation.
Parameters
- quality: string
  ASCII quality string
- encoding: QualityEncoding = "phred33"
  Quality encoding scheme
Returns number
Average quality score
Example
```
const avg = calculateAverageQuality('IIIIIIIIII', 'phred33'); // 40
```
- Defined in src/operations/core/quality/statistics.ts:99