Update operator fee NAT test to verify there is no chain split

[teddyknox]

Test Procedure

1. Setup Phase

   • Acquires test wallets with funds for both L1 and L2 chains
   • Sets up the test environment for the Isthmus fork with 2 L2 nodes
   • Establishes connections to L1 and L2 clients
   • Funds the rollup owner wallet with 10 ETH

2. Test Cases
   The test runs through 4 different operator fee configurations:

   a. Zero fees:
      - Constant: 0
      - Scalar: 0%
      - Expected: No operator fee charged
   
   b. Constant fee only:
      - Constant: 1000
      - Scalar: 0%
      - Expected: Only fixed fee component
   
   c. Scalar fee only:
      - Constant: 0
      - Scalar: 5% (500 basis points)
      - Expected: Fee proportional to base fee
   
   d. Both constant and scalar:
      - Constant: 1000
      - Scalar: 5%
      - Expected: Both fixed and proportional components
   

3. For Each Test Case

   • Updates operator fee parameters in the SystemConfig contract
   • Verifies the parameters were set correctly
   • Waits for L2 nodes to sync with L1 (2 minutes)
   • Takes initial balance snapshots of relevant accounts:
     • Base Fee Vault
     • L1 Fee Vault
     • Sequencer Fee Vault
     • Operator Fee Vault
     • Test Wallet
   • Sends a test transaction (0.1 ETH transfer)
   • Takes final balance snapshots
   • Calculates expected fee changes based on:
     • Base fee burned
     • L1 fee
     • L2 fee (sequencer fee)
     • Operator fee
   • Verifies actual balance changes match expected calculations

4. Verification Points

   • Confirms GPO (Gas Price Oracle) contract has correct Isthmus view
   • Verifies L1 fee calculations match between:
     • Local calculation
     • GPO contract calculation
     • Transaction receipt
   • Ensures all fee vault balances change as expected
   • Validates wallet balance changes match total fee deductions

5. Cleanup

   • Returns any remaining funds from the rollup owner wallet back to the funding wallet

The test is designed to comprehensively verify that operator fees are calculated and distributed correctly under different fee models, ensuring the economic mechanisms of the system work as intended.

[codecov]

Codecov Report

Attention: Patch coverage is 10.71429% with 175 lines in your changes missing coverage. Please review.

Project coverage is 42.13%. Comparing base (4764cdc) to head (06a09c8).
Report is 7 commits behind head on develop.

Files with missing lines	Patch %	Lines
devnet-sdk/testing/systest/multi_client.go	0.00%	131 Missing ⚠️
devnet-sdk/testing/testlib/validators/nodes.go	0.00%	27 Missing ⚠️
devnet-sdk/shell/cmd/enter/main.go	0.00%	9 Missing ⚠️
devnet-sdk/system/chain.go	50.00%	3 Missing and 2 partials ⚠️
devnet-sdk/shell/env/chain.go	84.21%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #14972      +/-   ##
===========================================
- Coverage    46.29%   42.13%   -4.17%     
===========================================
  Files         1160      990     -170     
  Lines        99562    89528   -10034     
===========================================
- Hits         46093    37720    -8373     
+ Misses       50147    48654    -1493     
+ Partials      3322     3154     -168     

Flag	Coverage Δ
cannon-go-tests-32	?
cannon-go-tests-64	?
contracts-bedrock-tests	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
devnet-sdk/shell/env/chain.go	78.49% <84.21%> (-2.41%)	⬇️
devnet-sdk/system/chain.go	65.16% <50.00%> (-1.94%)	⬇️
devnet-sdk/shell/cmd/enter/main.go	0.00% <0.00%> (ø)
devnet-sdk/testing/testlib/validators/nodes.go	0.00% <0.00%> (ø)
devnet-sdk/testing/systest/multi_client.go	0.00% <0.00%> (ø)

... and 185 files with indirect coverage changes

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[teddyknox]

Depends on ethereum-optimism/infra#261