fix(starknet): increase paymaster resource bounds

[tarrencev]

Summary

• increase Starknet paymaster resource-bound multiplier from 1.5x to 2.5x
• add unit coverage for gas amount and gas price scaling, including L1 data gas

Context

This should address failures like Insufficient max L1DataGas: max amount: 1440, actual used: 1504 by giving submitted transactions additional resource-bound headroom without going all the way to the legacy 4.5x multiplier.

Test

• cargo +1.88.0 fmt --all
• cargo +1.88.0 test -p paymaster-starknet transaction::gas
• cargo +1.88.0 test -p paymaster-starknet