feat(security): add stake-weighted PBFT, merkle sync verification, and hotkey rate limiting

- Add stake_weighted_pbft.rs: PBFT with stake-weighted voting (50%+ stake required)
- Add merkle_verification.rs: cryptographic verification for state sync data
- Update p2p_sync.rs: reject entries failing merkle verification
- Update protection.rs: rate limiting by hotkey (prevents peer_id bypass)
- Add double-vote prevention (first vote wins)
- Add hotkey blacklisting with automatic disconnect

Security fixes for:
1. Votes now weighted by validator stake, not count
2. State sync entries verified against merkle root
3. Double-voting prevented in consensus
4. Rate limits tied to cryptographic identity

Author: EchoBT

crates/consensus/src/lib.rs

@@ -28,11 +28,13 @@
 pub mod governance_integration;
 pub mod pbft;
 pub mod stake_governance;
+pub mod stake_weighted_pbft;
 pub mod state;
 pub mod types;
 
 pub use governance_integration::*;
 pub use pbft::*;
 pub use stake_governance::*;
+pub use stake_weighted_pbft::*;
 pub use state::*;
 pub use types::*;