[Good First Issue]: Add `CONTRIBUTING.md` section on running the fuzz targets locally

[AteebNoOne]

Description

The repo has cargo-fuzz harnesses (fuzz_parse, fuzz_roundtrip, fuzz_capi) per the roadmap, but CONTRIBUTING.md doesn't currently explain how a new contributor should install cargo-fuzz, run a target, and interpret a crash artifact.

Acceptance Criteria

• CONTRIBUTING.md includes a "Fuzz Testing" section with: install instructions (cargo install cargo-fuzz), commands to run each of the 3 fuzz targets, how to reproduce a crash from a saved artifact, expected minimum fuzz run time before considering a change "fuzzed"
• Instructions verified to work on a clean checkout

Helpful Resources & Context

• fuzz/ directory in the repo
• ROADMAP.md Phase 7 — Fuzz testing deliverables
• cargo-fuzz docs: https://rust-fuzz.github.io/book/cargo-fuzz.html

Implementation Notes

Documentation-only task, no code changes needed. Good first PR for someone wanting to get familiar with the test/fuzz setup before tackling code issues.

[anidroid1184]

Hi @AteebNoOne , can you asing me this issue?

[anidroid1184]

Hi @AteebNoOne, i'll been working on this issue tomorrow.