feat: add case sensitivity debug logging to search algorithm

[roomote]

This PR addresses issue #4731 by adding case sensitivity detection and debug logging to the search and replace algorithm.

Changes

• Enhanced error messages: When a search fails, the algorithm now detects if there are potential case mismatches in the file and includes this information in the error message
• Debug logging: Added console logging when case sensitivity issues are detected, helping AI assistants understand why modifications might be failing
• Improved diagnostics: The error messages now include a count of potential case mismatches found in the file

Implementation Details

1. Multi-search-replace.ts:

   • Added case mismatch detection when no match is found
   • Logs case differences when search and replace content differ only by case
   • Shows "Potential case mismatch" indicator with count in error messages

2. Multi-file-search-replace.ts:

   • Similar implementation for multi-file operations
   • Consistent logging format for debugging

3. Tests:

   • Added comprehensive test coverage for case sensitivity detection
   • Tests verify both error messages and console logging behavior

Example Output

When a case mismatch is detected, the error message will include:

No sufficiently similar match found (75% similar, needs 100%)

Debug Info:
- Similarity Score: 75%
- Required Threshold: 100%
- Search Range: start to end
- Tried both standard and aggressive line number stripping
- 🔍 **Potential case mismatch**: Found 2 location(s) where content differs only by case

And the console will log:

[apply_diff] Case sensitivity issue detected: 2 potential matches with different casing

This helps AI assistants understand that the issue might be related to case sensitivity rather than the content being completely different.

Fixes #4731

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Important

Adds case sensitivity detection and logging to search and replace algorithm, enhancing error messages and diagnostics.

• Behavior:
  • Adds case sensitivity detection and logging to multi-search-replace.ts and multi-file-search-replace.ts.
  • Enhances error messages with potential case mismatch information and count.
  • Logs case sensitivity issues to console.
• Tests:
  • Adds tests in multi-search-replace.spec.ts for case sensitivity detection and logging.
  • Verifies error messages and console logging behavior.

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[ellipsis-dev]

The block that detects case differences (using toLowerCase and comparing word-by-word) is duplicated across strategies. Consider extracting this logic to a shared utility function to reduce duplication and ease future maintenance.

^{This comment was generated because it violated a code review rule: irule_tTqpIuNs8DV0QFGj.}

[daniel-lxs]

These changes seem too complex, I think we should try simply adding a new suggestion to the suggested fixes list:

Suggested fixes:

1. Verify the search content exactly matches the file content (including whitespace)
2. Check for correct indentation and line endings
3. Use <read_file> to see the current file content
4. Consider breaking complex changes into smaller diffs
5. Ensure start_line parameter matches the actual content location

To check the case of the Search block.