MCP-04: add MCP transaction v1 parser and fee hooks

[aeyakovenko]

Summary

• add MCP Transaction v1 parser/serializer in agave-transaction-view (transaction-view/src/mcp_transaction.rs) for deterministic wire handling
• parse and expose MCP config-mask fields including inclusion_fee, ordering_fee, and target_proposer
• add non-breaking fee integration hooks in solana-fee:
  • calculate_fee_details_with_mcp(...)
  • apply_mcp_fee_components(...)
• apply MCP fee components as:
  • inclusion_fee -> transaction fee component
  • ordering_fee -> prioritization fee component
• add targeted unit tests for roundtrip parsing, deterministic field extraction, parse rejection behavior, and MCP fee component application

Testing

• cargo test -p agave-transaction-view mcp_transaction -- --nocapture
• cargo test -p solana-fee -- --nocapture

Closes #19