Add an opt-in preflight that excludes only guaranteed tracked renames
from the max-delete count. Reuse normal bisync listing metadata,
validate strategy and flag conflicts early, and skip preflight work
when --force bypasses the safety check.
The max_delete_track_renames scenario uses the default hash
track-renames strategy, which requires a hash common to both paths.
Skip it on remote combinations without one, such as crypt, instead of
failing the integration tests.
Fixes#8685
Morax
49158b2d9f