refactor(hashline-edit): enforce three-op edit model

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.

src/tools/hashline-edit/index.ts

@@ -8,14 +8,9 @@ export {
 export { parseLineRef, validateLineRef } from "./validation"
 export type { LineRef } from "./validation"
 export type {
-  SetLine,
-  ReplaceLines,
-  InsertAfter,
-  InsertBefore,
-  InsertBetween,
-  Replace,
-  Append,
-  Prepend,
+  ReplaceEdit,
+  AppendEdit,
+  PrependEdit,
   HashlineEdit,
 } from "./types"
 export { NIBBLE_STR, HASHLINE_DICT, HASHLINE_REF_PATTERN, HASHLINE_OUTPUT_PATTERN } from "./constants"
@@ -23,8 +18,6 @@ export {
   applyHashlineEdits,
   applyInsertAfter,
   applyInsertBefore,
-  applyInsertBetween,
-  applyReplace,
   applyReplaceLines,
   applySetLine,
 } from "./edit-operations"