feat(hashline-edit): add autocorrect, BOM/CRLF normalization, and file creation support

Implements key features from oh-my-pi to improve agent editing success rates:

- Autocorrect v1: single-line merge expansion, wrapped line restoration,
  paired indent restoration (autocorrect-replacement-lines.ts)
- BOM/CRLF normalization: canonicalize on read, restore on write
  (file-text-canonicalization.ts)
- Pre-validate all hashes before mutation (edit-ordering.ts)
- File creation via append/prepend operations (new types + executor logic)
- Modular refactoring: split edit-operations.ts into focused modules
  (primitives, ordering, deduplication, diff, executor)
- Enhanced tool description with operation choice guide and recovery hints

All 50 tests pass. TypeScript clean. Build successful.

src/tools/hashline-edit/index.ts

@@ -7,7 +7,17 @@ export {
 } from "./hash-computation"
 export { parseLineRef, validateLineRef } from "./validation"
 export type { LineRef } from "./validation"
-export type { SetLine, ReplaceLines, InsertAfter, InsertBefore, InsertBetween, Replace, HashlineEdit } from "./types"
+export type {
+  SetLine,
+  ReplaceLines,
+  InsertAfter,
+  InsertBefore,
+  InsertBetween,
+  Replace,
+  Append,
+  Prepend,
+  HashlineEdit,
+} from "./types"
 export { NIBBLE_STR, HASHLINE_DICT, HASHLINE_REF_PATTERN, HASHLINE_OUTPUT_PATTERN } from "./constants"
 export {
   applyHashlineEdits,