feat: implement transaction prioritization and fee policy

[hominlee-wemade]

Description

This PR implements transaction prioritization and fee policy updates to support Authorized Accounts in StableNet, addressing the requirements outlined in #5 and #22.

Overview

This update introduces two major improvements:

1. Transaction Ordering Enhancement
   Transactions from Authorized Accounts (accounts that have completed KYC or similar authentication processes) are now prioritized over normal accounts in the mempool. This ensures that authenticated institutional transactions receive preferential treatment even during network congestion.
2. Fee Policy Update
   Authorized Accounts: Gas fees are calculated based on the actual priority fee (GasTipCap) specified in the transaction
   Normal Accounts: Gas fees are capped at a pre-agreed HeaderGasTip value, regardless of the priority fee they submit

Summary of Changes

1. Transaction Prioritization Rules

• Between Authorized Accounts:
  • Higher fee transactions have priority
  • If fees are equal, earlier received transactions have priority
• Between Normal Accounts:
  • Prioritized by reception order only (no fee comparison)
• Authorized vs Normal Accounts:
  • Authorized Account transactions are always prioritized

2. Fee Policy

• Authorized Accounts: Use the transaction’s GasTipCap() (priority fee).
• Normal Accounts: Use the fixed HeaderGasTip defined in the block header.

3. Transaction Eviction Rule (When the transaction pool is full)

• Original Eviction Rules
  • When baseFee exists:
    → lower EffectiveGasTip(baseFee) → lower GasFeeCap → lower GasTipCap → higher nonce
  • When baseFee does not exist:
    → lower GasFeeCap → higher nonce
• Updated Eviction Rules (with Anzeon)
  • Anzeon Disabled:
    → Use the original logic unchanged.
  • Anzeon Enabled:
    → Authorized Accounts: Apply original eviction logic using transaction's actual GasTipCap
    → Normal Accounts: Apply original eviction logic but use HeaderGasTip instead of transaction's GasTipCap

Related Issues

• Close Mechanism for prioritizing Minter's transaction requests #5 – Mechanism for prioritizing Minter’s transaction requests
• Implement Regulatory Compliance Features: Blacklist and Authorized Accounts #22 – Authorized Account Concept

[0xmhha]

I've added some code suggestions that need review