Semantic Cache Implementation

Implement a semantic caching layer for LLM responses.

## Requirements
{{cache_requirements}}

## Technology Stack
{{tech_stack}}

## Expected Query Volume
{{queries_per_day}}

Provide a complete implementation including:

```python
# 1. Cache key generation using embeddings
# 2. Similarity threshold configuration
# 3. Cache invalidation strategy
# 4. Hit/miss metrics collection
# 5. Fallback handling
```

Include:
- Trade-offs between similarity thresholds
- Memory estimation formulas
- Cache warming strategies
- Monitoring dashboards configuration