Release 5.0.10: generator dashboard and reward-cache safety

[dylanuys]

Promotes testnet to main and bumps VERSION and gas/init.py to 5.0.10.

• Rich/Plotext generator performance dashboard: image/video fool-rate history, verification stats, current incentive, and recent chain-verified submission/reveal context with separate event tracks (Add Rich and Plotext performance dashboard to gascli g perf #467).
• Includes the pending 5.0.9 reward-cache safety changes: preserve scores and resubmit persisted hotkey payouts during reward-database outages (Keep submitting last-good payouts during reward database outages #466).
• Required bmcore history and verification fixes are already deployed. No new migrations or reward-threshold changes.

Validation: 307 tests pass on the release tree; lint and lockfile checks pass.