Responsive Layout Implementation

[AnuKritiW]

This PR implements a fully responsive layout system that adapts to window resizing while preserving the original 3:1 panel proportion ratio and maintaining usability across different viewport sizes.

Smart Panel Resizing

• Proportional scaling: Maintains original 3:1 ratio between top and bottom panel rows
• Minimum size enforcement: Bottom panels never shrink below usable dimensions
• Internal scrolling: Content scrolls within panels when space becomes constrained
• No overflow: Layout stays within viewport bounds with dark theme consistency

WebGPU Canvas Auto-Resize

• Responsive rendering: Canvas automatically adjusts resolution on window resize
• Device pixel ratio support: Maintains crisp rendering on high-DPI displays
• Test-safe implementation: Environment checks prevent test failures

Texture Thumbnails

• Flexible wrapping: Thumbnails reflow from horizontal row → 2×2 grid → vertical stack
• Uniform sizing: All 4 thumbnails maintain identical dimensions regardless of layout
• Dynamic scaling: Responsive sizing with minimum width constraints

Mesh Panel Buttons

• Smart text truncation: Long button text shows ellipsis ("Select..." instead of overflow)
• Flexible layout: Buttons wrap to multiple rows when panel width is constrained
• Natural sizing: Maintains button proportions without forced stretching

Responsive Component Architecture

• Flex-based panels: Each panel uses internal flexbox for content management
• Min-height patterns: min-height: 0 enables proper shrinking behavior
• Conditional scrolling: Overflow handling moves inside components

Impact

• Seamless resizing: Smooth adaptation to window size changes
• Content preservation: No information loss during responsive transitions
• Visual consistency: Dark theme maintained throughout scrollable areas
• Intuitive behavior: Layout changes feel natural and predictable

Closes #84