Vector Similarity Threshold Tuner

Tune vector similarity thresholds for optimal retrieval quality.

## Current Configuration
{{current_config}}

## Evaluation Dataset
{{eval_dataset}}

## Quality vs Quantity Goals
{{quality_goals}}

Implement threshold tuning:

```python
class SimilarityThresholdTuner:
    def evaluate_threshold(self, threshold: float, eval_data: List[EvalPair]) -> ThresholdMetrics:
        """
        Metrics:
        - Precision at threshold
        - Recall at threshold
        - F1 score
        - Average results per query
        """
        pass
    
    def find_optimal_threshold(self, eval_data: List[EvalPair], optimize_for: str) -> float:
        """Grid search for optimal threshold"""
        pass
    
    def analyze_distribution(self, similarities: List[float]) -> DistributionAnalysis:
        """Analyze similarity score distribution"""
        pass
    
    def generate_report(self, thresholds: List[float], metrics: List[ThresholdMetrics]) -> str:
        """Visual report of threshold trade-offs"""
        pass
```

Include:
- Per-query-type analysis
- Confidence intervals
- Production recommendation