Add RRD loading metrics tracking with UI visualization

Implements metrics tracking for RRD file loading when
profiling is active. Tracks the complete pipeline
from file loading through playback completion with
detailed timing breakdowns and a visual timeline display.
Also prints performance breakdown to the console.

Metrics tracked:
- Time to first message
- Stream latency
- Ingestion lag time
- Playback time
- Message throughput (msgs/sec)
- Total end-to-end loading time

Author: joelreymont