Subfolder Exploration & Flatten View

New features

• Added recursive search and display for subfolder files
• Added right-side context pane
• Displayed total file count per Space in the sidebar
• Introduced Dashboard (statistics for file counts, storage usage, etc.)
• Introduced Library page (quick access to all tags and memos)
• Added metadata copy functionality (memos, priority, tags)
• Added "View all sub-files" for specific Spaces
• Added file copy functionality
• Added drag-and-drop creation (save web images, create URL shortcuts, or save text snippets)
• Added "Scroll to Selected" button
• Added quick action buttons for editing priority, tags, and memos
• Added search precision toggle (Exact vs. Fuzzy match)
• Added customizable app startup page
• Added option to clear thumbnail cache

Improvements

• Added new tag badge colors
• Improved drag-to-select functionality
• Updated app icon
• Refined global UI/UX (colors, typography, spacing)
• Added sorting by name and file count in the tag list panel

Bug fixes

• Fixed text visibility in the tag edit dialog