Clean server close of bidi read stream treated as success with pending ranges

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

In `src/storage/src/storage/bidi/worker.rs`, when the server closes the bidi read stream, `Worker::run` handles `Ok(None)` by returning `Ok(())`:

https://github.com/googleapis/google-cloud-rust/blob/f02b42c2ac5720334cd2b5335824bd4166264527/src/storage/src/storage/bidi/worker.rs#L74

https://github.com/googleapis/google-cloud-rust/blob/f02b42c2ac5720334cd2b5335824bd4166264527/src/storage/src/storage/bidi/worker.rs#L98-L101

The worker returns success without verifying that `self.ranges` is empty. Any pending readers observe a stream EOF and treat the truncated read as success.

Furthermore, exiting `Worker::run` drops the `requests` channel receiver while the parent `ObjectDescriptor` remains live. Any subsequent `read_range()` call on the `ObjectDescriptor` panics on `.expect("worker never exits while ObjectDescriptor is live")`:

https://github.com/googleapis/google-cloud-rust/blob/f02b42c2ac5720334cd2b5335824bd4166264527/src/storage/src/storage/bidi/transport.rs#L135-L138

Read Worker::run in src/storage/src/storage/bidi/worker.rs, especially its Ok(None) handling, then trace read_range() and the request channel in src/storage/src/storage/bidi/transport.rs. Confirm the behavior with pending ranges and a later read_range() call; done means truncated reads are not reported as successful and a live ObjectDescriptor does not panic after clean server closure.

Written by the indexing model from the issue text.