Feature: opt out of erc-4337

[Oxbobby]

Summary

• Replaces custom gas price sampling from full block transaction data with viem fee estimation.
• Uses eth_feeHistory for EIP-1559 priority fee guidance, with fallback to viem fee estimation if fee history fails.
• Adds the erc4337 feature flag, enabled by default.
• Threads the ERC-4337 flag through account creation, estimation, gas price fetching, paymaster setup, transfers, swaps, and dapp requests.
• Disables ERC-4337-dependent behavior when the flag is off:
  • bundler gas price fetching
  • bundler estimation support for EOA7702, V2, and Safe accounts
  • V2 internal/gas tank fee options
  • swap sponsorship
  • paymaster service
  • EOA transaction recording used for Gas Tank
• Adds enableErc4337AndReestimate() so the UI can re-enable smart account fee options and refresh estimation.
• Adds/updates tests for gas price fetching, account fee options, and swap sponsorship gating.