- Add GET /api/indicators/coverage/{symbol}/{interval} to check coverage
- Add GET /api/indicators/coverage/all for system-wide coverage status
- Add POST /api/indicators/backfill/{symbol}/{interval} to backfill missing indicators
- Add POST /api/indicators/backfill-all for bulk backfill operations
- Add GET /api/indicators/missing/{symbol}/{interval} to list incomplete records
- Add GET /api/indicators/summary for aggregate coverage statistics
- Support configurable batch_size and min_coverage_threshold parameters
- Return detailed results including before/after coverage percentages
- Provide summary statistics with coverage ranges and lowest coverage pairs
- Enable UI integration for monitoring and managing indicator completeness
These endpoints expose the db.py indicator coverage methods through the
web API, allowing users to monitor and maintain 100% technical indicator
coverage across all trading pairs via the web interface.