Implement /api/getStatistics endpoint

## Description
Implement the \`/api/getStatistics\` Pages Function endpoint.

- Call vm-sdk \`getStatistics()\`
- Cache with Cache API using 1hr TTL
- No query parameters required
- **Returns**: pool statistics

## Files
- Create \`functions/api/getStatistics.ts\`

## Roadmap
Task 2.16