fix: handle root directory startup error from Claude Desktop

- When started from Claude Desktop, working directory might be "/"
- Now defaults to user home directory if cwd is "/"
- Startup scripts change to script directory for consistency
- Simplified README to remove implementation details about PROJECT_ROOT

This fixes the "MCP_PROJECT_ROOT cannot be set to '/'" error
while maintaining security by preventing filesystem-wide access.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

run_gemini.bat

@@ -4,6 +4,9 @@ REM Windows batch script to run Gemini MCP server
 REM Get the directory where this script is located
 set SCRIPT_DIR=%~dp0
 
+REM Change to script directory to ensure proper working directory
+cd /d "%SCRIPT_DIR%"
+
 REM Check if virtual environment exists
 if exist "%SCRIPT_DIR%venv\Scripts\activate.bat" (
     REM Activate the virtual environment