fix(torngit): handle ValueError in diff_to_json unpacking

[sentry]

This PR addresses a ValueError: not enough values to unpack (expected 2, got 1) occurring in shared/torngit/base.py within the diff_to_json method.

The root cause was identified as diff_to_json's naive string splitting by "\ndiff --git a/". When a file's patch content (e.g., a test fixture or embedded patch) itself contained a line starting with diff --git a/, it created a spurious extra split point. This resulted in a malformed diff chunk whose first 'line' lacked the expected " b/" separator, causing the split(" b/", 1) call to return only one element, leading to the ValueError during tuple unpacking.

The fix extends the existing except IndexError clause to also catch ValueError. The subsequent fallback logic, which scans for --- a/ and +++ b/ lines, is already robust enough to handle these malformed chunks by either correctly identifying the filenames or, if no valid headers are found, allowing the chunk to be safely skipped.

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Fixes WORKER-Z8M

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[codspeed]

Merging this PR will not alter performance

✅ 9 untouched benchmarks

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_{Comparing seer/fix/diff-to-json-valueerror-hjcxhT (3fe1384) with main (17e0f08)¹}

Footnotes

1. No successful run was found on main (1c2ed4e) during the generation of this report, so 17e0f08 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

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