fix(test-client-clis): write empty trace placeholder for rejected txs

[leolara]

🗒️ Description

Extends #2709 to fix a disk/in-memory asymmetry that caused --verify-traces to report spurious divergences for transactions that produce a receipt but no TransactionEnd tracer event (e.g. EIP-3607 collisions, CREATE-into-non-empty failures during process_transaction).

#2709 made the in-memory collect_traces tolerant of a missing trace-N-<hash>.jsonl by appending an empty TransactionTraces. The same placeholder was not written to --evm-dump-dir, so a later --verify-traces run loaded a different shape from disk and the comparator's outer length check fired a TransactionCountMismatch for every affected test.

This PR makes the on-disk representation symmetric with the in-memory one (Option A from the issue):

• TransitionTool.collect_traces: when the missing-file branch runs and debug_output_path is set, write a zero-byte trace-{i}-{hash}.jsonl placeholder.
• TransactionTraces.from_file: return an empty TransactionTraces for empty files (the loader path used by _load_traces_from_dump_dir).

Verification

The issue's reproducer (the three EIP-3607 / CREATE-collision tests) now compares clean:

Before:  Total: 24, Equivalent:  0, Divergent: 24   (per-test from issue)
After:   Total: 78, Equivalent: 78, Divergent:  0   (all 3 tests, exact-no-stack)

Unit coverage added:

• test_transition_tool.py: placeholder is written when debug_output_path is set; not written when it is None (in-memory padding still happens).
• test_verify_traces.py: loader reads an empty placeholder file as an empty TransactionTraces slot.

🔗 Related Issues or PRs

Fixes #2758. Extends #2709.

✅ Checklist

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

  just 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).
• Tests: Ran mkdocs serve locally and verified the auto-generated docs for new tests in the Test Case Reference are correctly formatted.
• Tests: For PRs implementing a missed test case, update the post-mortem document to add an entry the list.
• Ported Tests: All converted JSON/YML tests from ethereum/tests or tests/static have been assigned @ported_from marker.

Cute Animal Picture

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