✨ Reflect External File Updates in Open Files #1826

Description

CodeEdit currently does not reflect changes made to a file outside of the application. This enhancement would introduce support for external file modification detection, ensuring that the editor stays in sync with the file system and prevents potential data loss or confusion for the user.

Expected Behavior

• CodeEdit detects external file modifications in real time or on focus regain
• If the file in CodeEdit has no unsaved changes, it should automatically reload the latest version from disk
• If the file has unsaved changes, CodeEdit should:
• Alert the user that the file has been modified externally
• Offer options such as:
• Discard local changes and reload from disk
• Keep current changes and overwrite on save
• View a diff or merge the changes (future enhancement)

Additional Context

• This feature is especially important for collaborative or multi-tool workflows, build processes that modify files, or using tools like Git that check out different versions of files.
• File watching should be performant and scalable (e.g., via FSEvents on macOS or DispatchSourceFileSystemObject) and resilient across large projects.
• Behavior should align with user expectations from other editors (Xcode, VS Code, etc.) but also respect CodeEdit’s design philosophy of clarity and safety.

Edge Cases to Consider

• Symbolic links
• Deleted or renamed files
• Files restored from trash or replaced
• Line ending or encoding changes
• Hidden files modified by scripts