Update settings.dart

[akshit397a]

Organized Layout:

Added descriptive headers and structured sections
Implemented a scrollable container to handle varying screen sizes
Improved spacing and padding for better readability

Visual Enhancements:

Added elegant card containers with subtle shadow effects
Included proper corner radius for a modern look
Implemented custom icons with contextual coloring for each setting

Theme Setting Improvements:

Added visual icons for each theme option (light, dark, system)
Improved radio button styling with custom colors
Enhanced visual feedback for selected options

Browser Preference Setting:

Added descriptive subtitle text
Improved toggle switch with matching icon that changes based on selection
Added proper spacing and dividers

Experimental Features Page:

Added a visually distinct warning banner with amber coloring
Organized features into a card with consistent styling
Enhanced feature toggles with descriptive elements
Implemented a more visually appealing app bar

Responsive Design:

Used proper scaling and responsive containers
Maintained consistent styling across different parts of the app
Added adaptive components that adjust to the device theme

Visual Consistency:

Used the app's color scheme throughout to maintain brand identity
Applied consistent spacing, shadows, and corner radii
Added subtle animations through Material inkwell effects