Fixes #4852: Add performance safeguards to prevent apply_diff hanging on large XML files

- Added maximum iteration limit (10,000) to fuzzySearch function
- Added 5-second timeout mechanism for very large files
- Added early exit when perfect matches are found
- Added performance logging for debugging large file issues
- Applied fixes to both MultiSearchReplaceDiffStrategy and MultiFileSearchReplaceDiffStrategy
- Added comprehensive test suite to verify the fix works correctly

The issue was caused by the middle-out search algorithm in fuzzySearch()
potentially running millions of iterations on large files without any
performance constraints, leading to indefinite hanging.

Author: roomote