fuzz-nightly: parse target crashed

[github-actions]

Nightly fuzz of the parse target failed.

Run: https://github.com/devrelaicom/compactp/actions/runs/26745654103
Artifacts: crash inputs were uploaded as workflow artifacts (look for fuzz-crashes-parse-26745654103).

Next steps:

1. Download the crash artifact from the workflow run.
2. Reproduce locally with scripts/fuzz.sh --target parse --duration 1 or directly via cat fuzz/artifacts/parse/<input> | cargo +nightly fuzz run parse.
3. Fix and add a reduced reproducer as a unit test in the relevant grammar module.