refactor(study-options): wire StudyOptionsFragment to use ViewModel

Replace direct collection access and mutable state in the fragment with
ViewModel delegation. The fragment now observes StudyOptionsState via
StateFlow and delegates operations (refresh, rebuild, empty, unbury) to
StudyOptionsViewModel. Removes currentContentView, updateValuesFromDeckJob,
retryMenuRefreshJob, and the col property getter.

Author: criticalAY