RGminer EXFER performance, watchdog, multi-pool failover

rgminer 0.7.5

• Improved EXFER Argon2id hashrate by approximately 7% through hasher-side performance optimizations.
• Added watchdog support for GPU failure handling, including HiveOS error reporting with GPU and PCI bus details.
• Added multi-pool stratum configuration with automatic failover and pool switching when the active endpoint fails or stops providing jobs.