SIMD-0138: Deprecate legacy vote instructions

SIMD-0138 (Deprecate legacy vote instructions) is a Core Standard Solana Improvement Document by Ashwin Sekar; proposal status Activated.

Active on mainnet-beta since epoch 656; active on testnet since epoch 671; active on devnet since epoch 730.

Feature gates

• Feature gate: Deprecate unused legacy vote tx plumbing
• Related gate: Enable tower sync vote instruction

Vortex

• Consensus leaderboard
• Fees leaderboard
• Validators
• Stake pools
• Decentralization
• Client versions
• Cluster status
• Governance
• Feature gates
• SIMDs
• Activity
• API and AI usage