Search files in project & replace already installed app

[vaibhavpandeyvpz]

Summary

Adds search functionality to the Files and Projects dock widgets, allowing users to quickly find items by name with real-time filtering.

Changes

• Added search boxes to Files and Projects dock widgets
• Implemented QSortFilterProxyModel for Files dock (QListView) with real-time filtering
• Implemented recursive filtering for Projects dock (QTreeWidget)
• Search boxes automatically clear when projects are opened/closed
• Case-insensitive search with clear button support
• Fixed QSortFilterProxyModel assertion error by properly mapping source indices to proxy indices in handleTabChanged()

Implementation Details

• Files dock uses QSortFilterProxyModel for efficient filtering of open files
• Projects dock uses recursive tree item filtering to show/hide matching items
• Search boxes use QSignalBlocker during model updates to prevent selection errors
• Fixed index mapping issues in handleTabChanged() to prevent proxy model assertion errors when tabs change
• Search boxes don't autofocus on startup (main window gets focus instead)

Usage

• Type in "Search in open files..." box to filter open files by name
• Type in "Search in project..." box to filter project tree items by name
• Search is case-insensitive and filters in real-time as you type
• Search boxes automatically clear when a new project is opened or all tabs are closed

Testing

• Build and run application
• Test search functionality in Files dock with multiple open files
• Test search functionality in Projects dock with project tree items
• Verify search boxes clear when projects are opened/closed
• Verify no QSortFilterProxyModel assertion errors occur when switching tabs
• Verify search boxes don't autofocus on startup but can still be clicked to focus