[c-bata]

Motivation

may_omit_trials() is documented as "Return True if this storage view may omit discarded trials." InMemoryStorage and SQLite3Storage return their apply_discard option, but JournalStorage returned whether a discarded trial had already been replayed. As a result, a JournalFileStorage created with apply_discard=True reported False until the first discard was applied.

Changes

• Return apply_discard from JournalStorage::may_omit_trials(), consistent with InMemoryStorage and SQLite3Storage.
• Add a Rust test checking that may_omit_trials() follows apply_discard both before and after a discard.
• Add a Python test checking that JournalFileStorage(..., apply_discard=True).may_omit_trials() is True before any trial is discarded.