Problem: unused variables (undo_state, sha_result, date match
captures) and duplicate if/else branches in gcal sync triggered
selene warnings and errors.
Solution: prefix unused state with underscore, simplify date
validation to a single pattern match, remove dead sha_result
call, and merge duplicate event deletion branches into a single
condition.
Problem: need test coverage for core data operations, inline
metadata parsing, and buffer diff algorithm.
Solution: add busted specs for store CRUD, round-trip
preservation, parse body/command_add with configurable date
syntax, and diff create/delete/update/copy/move operations.
