Changes view: show changed file permissions

Current Behavior:

SmartGit’s Changes pane currently displays the unchanged file content twice when only a file’s permissions have changed. However, it does not show the actual mode difference (e.g., 100644 → 100755), making it difficult to audit permission changes without switching to external tools like the Git CLI.

Proposed Enhancement:

Display the exact file mode change inline in the Changes pane, such as:
File mode changed: 100644 → 100755

This should appear clearly above or alongside the diff view when no content changes are present.

Benefits:

• Improves visibility of non-content changes
• Helps developers catch unintended permission toggles
• Reduces reliance on Git CLI for metadata inspection
• Enhances trust and transparency in cross-platform workflows