FEATURE: Add time-series and historical trend visualization #63
Description
Timeseries Metrics Service: This process supports historical trend analysis without introducing external dependencies. This component polls metrics from Valkey clusters or instances at configurable intervals, with default settings to be determined based on further testing and server load analysis. It writes data to efficient local storage, enabling time-series visualizations of CPU load, memory usage, hot keys, and hot slots. Future plans include the ability to store metrics in remote storage (such as S3 or a timeseries DB). While it runs locally by default, the service can also be deployed remotely.
The standalone metrics server connects directly to Valkey, polls metrics (like MEMORY STATS, INFO CPU, COMMANDLOG, MONITOR) at fixed intervals, and writes them to daily NDJSON files. It batches data to reduce I/O and includes retry and backoff mechanisms for resilience. Each API endpoint (/memory, /cpu, etc.) reads and returns recent NDJSON rows, supporting filtering by time in future extensions.