🧹 fix(dav): replace unwrap() with infallible primitive cast in seek

[google-labs-jules]

🎯 What: Removed usages of unwrap() by replacing the try_into().unwrap() calls with infallible as u64 casts in bepository-dav/src/lib.rs.
💡 Why: unwrap() inside the library function could potentially panic. Because n is already known to be positive (n >= 0) from the condition check before the cast, converting i64 to u64 via the primitive as operator is completely safe and robust. This removes the implicit panic branches and improves the overall robustness of the codebase.
✅ Verification: Re-ran cargo test -p bepository-dav, cargo clippy, and cargo fmt. All checks passed.
✨ Result: Enhanced the library's readability and correctness by enforcing structurally safe primitive type conversions.

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PR created automatically by Jules for task 11861442965727072310 started by @unbrice

[google-labs-jules]

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