feat(context-menu): add duplicate file functionality

[PrayagCodes]

Description

This PR adds a "Duplicate" option to the file context menu, allowing users to create a copy of a file in the same directory with automatic name deduplication.

Problem Statement

Currently, users must manually use Copy (Ctrl+C) and Paste (Ctrl+V) to duplicate files, which doesn't automatically generate unique filenames. This creates friction in the user workflow and requires manual renaming to avoid conflicts.

Solution

Added a "Duplicate" menu item to the file context menu that:

• Creates a copy of the selected file in the same directory
• Automatically generates unique filenames using sequential numbering
• Only appears for files (not directories)
• Is excluded from trash/trashed items

Changes Made

Frontend Changes

• src/gui/src/UI/UIItem.js: Added duplicate menu item with onClick handler (lines 1250-1271)
• src/gui/src/i18n/translations/*.js: Added 'duplicate' translation key to all 37 language files

Technical Implementation

• Uses existing puter.fs.copy() API with dedupeName: true parameter
• Leverages backend's automatic filename deduplication logic
• Follows existing naming pattern: filename (1).ext, filename (2).ext, etc.
• Includes error handling with console logging

Testing

Manual Testing Performed

• Basic file duplication creates filename (1).ext
• Sequential duplicates create filename (2).ext, filename (3).ext, etc.
• Works with various file types: .txt, .html, .png, .zip
• Handles complex filenames: spaces, multiple extensions, no extensions
• Correctly hidden for directories
• Correctly hidden in trash

Test Cases

1. Right-click file → "Duplicate" appears in menu
2. Click "Duplicate" → new file appears with unique name
3. Duplicate again → sequential number increments
4. Right-click folder → "Duplicate" does not appear
5. Right-click file in trash → "Duplicate" does not appear