Rename Refactoring Tool Not Working

## Issue Summary
The `rename_refactoring` tool appears to be completely non-functional. It cannot locate **any** symbols (methods, variables, properties) regardless of their visibility or location, even when they are clearly present and found by other MCP tools. The Claude Code agent drafted the test cases below based on their repeated attempts to use this tool.

## Steps to Reproduce

### Test Case 1: Public Virtual Method
1. **Search for method** using `search_in_files_by_text`
```
Symbol: "GetPropertyNames"
Result: Assets\Components\TestComponent.Services.cs:17
```

2. **Verify method exists** using `get_file_text_by_path`
```csharp
public virtual string[] GetPropertyNames()
```

3. **Attempt rename** using `rename_refactoring`
```json
{
"pathInProject": "Assets\\Components\\TestComponent.Services.cs",
"symbolName": "GetPropertyNames",
"newName": "GetPropertyNamesAsync"
}
```

4. **Error received**
```
Couldn't find symbol 'GetPropertyNames' in file 'Assets\Components\TestComponent.Services.cs'
```

### Test Case 2: Public Field Variable
1. **Search for variable** using `search_in_files_by_text`
```
Symbol: "showAttributeGradient"
Result: Assets\Splines\SplineGroup.cs:28
```

2. **Verify variable exists** using `get_file_text_by_path`
```csharp
public bool showAttributeGradient = false;
```

3. **Attempt rename** using `rename_refactoring`
```json
{
"pathInProject": "Assets\\Splines\\SplineGroup.cs",
"symbolName": "showAttributeGradient",
"newName": "showGradientVisualization"
}
```

4. **Error received**
```
Couldn't find symbol 'showAttributeGradient' in file 'Assets\Splines\SplineGroup.cs'
```

## Expected Behavior
The rename refactoring should successfully locate and rename symbols that are found by search tools.

## Actual Behavior
**The tool is completely non-functional** - it cannot find any symbols regardless of type (methods, variables, properties) or visibility (public, private, protected).

## Environment
- **Platform**: Windows
- **IDE**: JetBrains Rider
- **Project Type**: Unity C#

## Additional Notes
- Other MCP tools work correctly (`search_in_files_by_text`, `get_file_text_by_path`, `get_symbol_info`)
- **Rename refactoring fails 100% of the time** on all tested symbols
- Tested multiple symbol types: methods, fields, etc. with different path types:

- Relative paths with backslashes
- Relative paths with forward slashes
- Absolute paths with backslashes
- Absolute paths with forward slashes