Harden block change handling and scheduling

[BlobMaster41]

Description

Avoid refreshing challenge solutions while the indexer is far behind by only calling onBlockChange when the block is within 10 blocks of the tip. Ensure verifyBlockHeight is always re-scheduled by moving the timeout into a finally block. Always trigger onBlockChange when the indexer progresses (remove the stale guard), but only advance OPNetConsensus height forward and swallow/set warnings on failures. Wrap transactionVerifier.onBlockChange and fee estimation in try/catch blocks to log warnings instead of failing the flow. Kept the old block-purge code commented.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Performance improvement
• Consensus change (changes that affect state calculation or validation)
• Refactoring (no functional changes)
• Documentation update
• CI/CD changes
• Dependencies update

Checklist

Build & Tests

• npm install completes without errors
• npm run build completes without errors
• npm test passes all tests

Code Quality

• Code follows the project's coding standards
• No new compiler warnings introduced
• Error handling is appropriate
• Logging is appropriate for debugging and monitoring

Documentation

• Code comments added for complex logic
• Public APIs are documented
• README updated (if applicable)

Security

• No sensitive data (keys, credentials) committed
• No new security vulnerabilities introduced
• RPC endpoints properly authenticated
• Input validation in place for external data

OP_NET Node Specific

• Changes are compatible with existing network state
• Consensus logic changes are documented and tested
• State transitions are deterministic
• WASM VM execution is reproducible across nodes
• P2P protocol changes are backward-compatible (or migration planned)
• Database schema changes include migration path
• Epoch finality and PoC/PoW logic unchanged (or documented if changed)

Testing

Consensus Impact

Related Issues

---

By submitting this PR, I confirm that my contribution is made under the terms of the project's license.