feat: improve settings page visual design

[prsauer]

Summary

• Reorganize settings into logical sections (Tooltip Data, Features, Developer) with gold-colored section headers
• Add horizontal divider lines between sections and below the title for visual hierarchy
• Display addon version next to the title and gearstick.io link in the footer
• Support Escape key to close the settings panel (matching other addon panels)
• Use darker background (0.05 vs 0.0) and GameFontHighlight for checkbox labels for better readability
• Fix RefreshConfigUI to respect setting defaults when refreshing checkbox states

Closes #23

Test plan

• Open the settings page via /gst config or the gear icon on the Summary panel
• Verify three sections appear: "Tooltip Data", "Features", "Developer" with gold headers
• Verify divider lines separate the title and sections
• Verify version number appears next to "GearStick Settings" title
• Verify "gearstick.io" appears in the bottom-right corner
• Toggle checkboxes on/off and confirm settings persist after closing/reopening
• Click "Reset All" and verify all checkboxes reset to defaults
• Click "Summary" button and verify it opens the summary panel
• Press Escape to close the settings panel
• Drag the panel by its title bar to confirm it's still movable

Munr-Job-ID: 81983186265c49d4bd8779d70ef62a43
Munr-Session-ID: n/a