Unify internal hashline edit handling around replace/append/prepend to remove legacy operation shapes. This keeps normalization, ordering, deduplication, execution, and tests aligned with the new op/pos/end/lines contract.
Unify hashline_edit input with replace/append/prepend + pos/end/lines semantics so callers use a single stable shape. Add normalization coverage and refresh tool guidance/tests to reduce schema confusion and stale legacy payload usage.
minpeter