Fix DevPanel alignment with centered game canvas

[kevinmaes]

Problem

The DevPanel is not properly aligned with the centered game canvas. The game was recently centered in a frame, but the DevPanel still uses absolute positioning with hardcoded dimensions.

Current Behavior

• DevPanel uses position: absolute with fixed 1280x720px dimensions (DevPanel.css:2-6)
• Game canvas is centered via flexbox layout
• DevPanel appears misaligned relative to the centered game

Desired Behavior

• DevPanel should align with the centered game canvas
• Should maintain proper positioning when window is resized

Files to Modify

• src/DevPanel/DevPanel.css - Fix positioning (lines 1-14)
• src/App.tsx - DevPanel is rendered at line 87 inside .app-stage-wrapper
• src/App.css - Parent layout uses flexbox with align-items: center (line 30)

Suggested Approach

• Remove position: absolute from DevPanel
• Let DevPanel flow naturally in the flexbox layout
• Adjust width to match game canvas width or use relative sizing
• Test that Cmd-D toggle still works correctly

Acceptance Criteria

• DevPanel is visually aligned with the centered game canvas
• Alignment is maintained on window resize
• Cmd-D toggle behavior remains unchanged