fix(tests): resolve transition fork blob methods in EIP-4844 conftest

[danceratopz]

🗒️ Description

Transition forks like ShanghaiToCancunAtTime15k inherit from TransitionBaseClass, not BaseFork, so they lack blob-related methods (blob_gas_per_blob, target_blobs_per_block, etc.). Calling these methods on a transition fork in the EIP-4844 conftest fixtures causes an AttributeError.

Fix: chain .transitions_to() before each blob method call — a no-op for regular forks, resolves to the target fork for transition forks. This is the established pattern used 30+ times across the codebase.

This bug is not caught in CI because test_blob_type_tx_pre_fork is marked @pytest.mark.slow and tox -e py3 runs with -m "not slow".

🔗 Related Issues or PRs

Blocks:

• feat(ci): split release builds across multiple runners; delete develop; stable becomes mainnet #2592
• A new fixture release.

✅ Checklist

• All: Ran fast tox checks to avoid unnecessary CI fails, see also Code Standards and Enabling Pre-commit Checks:

  uvx tox -e static

• All: PR title adheres to the repo standard - it will be used as the squash commit message and should start type(scope):.
• All: Considered updating the online docs in the ./docs/ directory.
• All: Set appropriate labels for the changes (only maintainers can apply labels).

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.24%. Comparing base (51fc631) to head (44e1688).
⚠️ Report is 15 commits behind head on forks/amsterdam.

Additional details and impacted files

@@                 Coverage Diff                 @@
##           forks/amsterdam    #2602      +/-   ##
===================================================
- Coverage            86.35%   86.24%   -0.12%     
===================================================
  Files                  599      599              
  Lines                36904    36984      +80     
  Branches              3771     3795      +24     
===================================================
+ Hits                 31868    31895      +27     
- Misses                4485     4525      +40     
- Partials               551      564      +13     

Flag	Coverage Δ
unittests	86.24% <ø> (-0.12%)	⬇️

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[spencer-tb]

LGTM! Thanks for catching this :)