Integer overflow in HTTP Range header calculation for large segment limits

Unconfirmed. This is the result of a search with Claude, may be a false positive.

When constructing the HTTP `Range` header in `read_object.rs`, `model_ext.rs` clamps offset and limit independently:

https://github.com/googleapis/google-cloud-rust/blob/f02b42c2ac5720334cd2b5335824bd4166264527/src/storage/src/storage/model_ext.rs#L287-L306

Then, in `read_object.rs`:

https://github.com/googleapis/google-cloud-rust/blob/f02b42c2ac5720334cd2b5335824bd4166264527/src/storage/src/storage/read_object.rs#L634

The expression `format!("bytes={o}-{e}", e = o + l - 1)` computes `o + l - 1` without checked or saturating arithmetic. For requests like `ReadRange::segment(1000, u64::MAX)`, `o + l` overflows, causing a panic in debug builds and integer wraparound in release builds.

Start by reading the offset and limit handling in src/storage/src/storage/model_ext.rs and the Range header construction in src/storage/src/storage/read_object.rs. Reproduce the issue with ReadRange::segment(1000, u64::MAX), then verify that large segment limits no longer overflow and that the resulting HTTP Range header remains correct.

Written by the indexing model from the issue text.