Fix whitespace issues and clean up lint warnings across codebase

[Beaulewis1977]

Summary

• Adds a new script fix_whitespace.py to automatically fix whitespace lint issues W293 (blank line contains whitespace) and W291 (trailing whitespace) in Python files.
• Cleans up trailing and extra whitespace in many source files across the project.
• Improves code formatting consistency by removing unnecessary blank lines and trailing spaces.

Changes

New Script

• fix_whitespace.py: Scans all Python files recursively, fixes whitespace issues, and reports summary.

Code Cleanup

• Removed trailing whitespace and fixed blank line whitespace in multiple files including:
  • build_all_platforms.py, build_installer/tray_app.py, build_installer/universal_document_converter.py, cli.py, cli_ocr.py, convert_recursive.py, convert_to_markdown.py, create_desktop_shortcut.py, create_executable.py, create_icon.py, create_installer.py, create_simple_installer.py, create_windows_installer.py, cross_platform modules, demo_system_tray.py, direct_launch.py, document_converter_gui.py, enhanced_system_tray.py, gui_ocr.py, install_converter.py, ocr_engine.py, ocr_engine/format_detector.py, ocr_engine/image_processor.py, ocr_engine/ocr_engine.py.
• Fixed inconsistent blank lines and spacing around imports, function definitions, and class methods.
• Improved readability by standardizing indentation and line breaks.

Test plan

• Run fix_whitespace.py to verify it correctly identifies and fixes whitespace issues.
• Run existing unit and integration tests to ensure no functional regressions.
• Manually verify UI components and CLI tools launch and operate normally.
• Confirm no trailing whitespace or blank line whitespace warnings remain in lint checks after applying the fixes.

🌿 Generated by Terry

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📎 Task: https://www.terragonlabs.com/task/ad8f7234-9800-4ba1-a269-c8dd9ea5e371