chore(tests): add genesis block header field BAL checklist

[shubham5080]

Summary

• Add test_bal_genesis for EIP-7928, covering the remaining checklist item block_header_field/test/genesis
• Genesis header must carry the empty BAL hash; block 1 verifies transfer activity is recorded in the BAL body
• Update eip_checklist_external_coverage.txt for general/code_coverage/missed_lines

Follows the same pattern as test_slotnum_genesis in EIP-7843.

Test plan

• uv run fill tests/amsterdam/eip7928_block_level_access_lists/test_fork_transition.py::test_bal_genesis --until=Amsterdam --clean

Checklist

• Ran fast static checks to avoid CI fails: just static
• PR title has the form <type>(<area>): <title>

Cute Animal Picture

Glamsterdam polar bear 🐻‍❄️

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.77%. Comparing base (ac0bf4f) to head (3cf1947).
⚠️ Report is 13 commits behind head on forks/amsterdam.

Additional details and impacted files

@@                 Coverage Diff                 @@
##           forks/amsterdam    #3416      +/-   ##
===================================================
+ Coverage            93.53%   93.77%   +0.23%     
===================================================
  Files                  624      624              
  Lines                37074    36905     -169     
  Branches              3394     3326      -68     
===================================================
- Hits                 34679    34606      -73     
+ Misses                1645     1597      -48     
+ Partials               750      702      -48     

Flag	Coverage Δ
unittests	93.77% <ø> (+0.23%)	⬆️

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[spencer-tb]

The BlockHeaderField.Test.Genesis item is indeed unmarked for 7928, although a dedicated test doesn't get us extra coverage here.

The genesis BAL is always empty, so every valid_from("Amsterdam") fixture already carries the only valid value. Could you instead, drop test_bal_genesis and add @EIPChecklist.BlockHeaderField.Test.Genesis() to test_bal_nonce_changes. And then also revert the missed_lines change in eip_checklist_external_coverage.txt?

It should just be a one line change!

b