feat(quickadapter): make label study schema reset configurable (#147)

feat(quickadapter): make label study schema reset configurable (#147)

* feat(quickadapter): make label study schema reset configurable

Add a boolean reset_label_study_on_schema_mismatch option that preserves the current reset behavior by default and lets operators retain incompatible label studies with a warning. Avoid rewriting incompatible selection metadata when preservation is selected, and fail closed when study inspection or deletion fails.

Refs #87

* docs(quickadapter): clarify reset_label_study_on_schema_mismatch fail-closed behavior

The `true` value keeps the historical destructive reset but no longer matches
main byte-for-byte on error paths: a study inspection error (either value) or a
deletion error (under `true`) now fails closed and aborts the optimization
instead of silently recreating or reusing the study. Reword the README tunable
description accordingly and align terminology with the neighboring entries.

* docs(quickadapter): tighten reset_label_study_on_schema_mismatch abort wording

Say the fail-closed paths abort study creation, matching the actual mechanism:
optuna_create_study returns None before the study is created, and the caller
then skips the optimization cycle.