refactor(hashline-edit): redesign hashline format with CID-based hashing

Breaking Changes:
- Change hashline format from 'lineNum:hex|content' to 'lineNum#CID:content'
- Replace hex-based hashing (00-ff) with CID-based hashing (ZPMQVRWSNKTXJBYH nibbles)
- Simplify constants: HASH_DICT → NIBBLE_STR + HASHLINE_DICT
- Update patterns: HASHLINE_PATTERN → HASHLINE_REF_PATTERN + HASHLINE_OUTPUT_PATTERN

Benefits:
- More compact and memorable CID identifiers
- Better alignment with LSP line reference format (lineNum#ID)
- Improved error messages and diff metadata clarity
- Remove unused toHashlineContent from diff-enhancer hook

Updates:
- Refactor hash-computation for CID generation
- Update all diff-utils to use new format
- Update hook to use raw content instead of hashline format
- Update tests to match new expectations

🤖 Generated with assistance of [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/hashline-edit-diff-enhancer/hook.ts

@@ -1,5 +1,5 @@
 import { log } from "../../shared"
-import { toHashlineContent, generateUnifiedDiff, countLineDiffs } from "../../tools/hashline-edit/diff-utils"
+import { generateUnifiedDiff, countLineDiffs } from "../../tools/hashline-edit/diff-utils"
 
 interface HashlineEditDiffEnhancerConfig {
 	hashline_edit?: { enabled: boolean }
@@ -86,16 +86,13 @@ export function createHashlineEditDiffEnhancerHook(config: HashlineEditDiffEnhan
 			}
 
 			const { additions, deletions } = countLineDiffs(oldContent, newContent)
-			const oldHashlined = toHashlineContent(oldContent)
-			const newHashlined = toHashlineContent(newContent)
-
 			const unifiedDiff = generateUnifiedDiff(oldContent, newContent, filePath)
 			
 			output.metadata.filediff = {
 				file: filePath,
 				path: filePath,
-				before: oldHashlined,
-				after: newHashlined,
+				before: oldContent,
+				after: newContent,
 				additions,
 				deletions,
 			}