Redesign timeline UI

[Microck]

Description

Redesign timeline UI with modern icon-based controls.

Type of Change

• New feature (non-breaking change which adds functionality)

Changes Made

• Replace text buttons with SVG icons
• Group controls visually with styled containers
• Style numeric inputs (removed native spinners)
• Play button with play/pause icon toggle
• Grid/guide control buttons with icons
• Guide mode hint chip
• Custom scrollbar styling
• Consistent button styling

Testing

• Tested in Firefox

Test Configuration:

• OS: Windows 10
• Browser: Firefox

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have tested my changes thoroughly

Related Issues

N/A

[immalloy]

these 3 buttons are the only ones that seem to not be working

[Microck]

@immalloy pushed updates on this one:

• fixed the 3 timeline controls on the right side (zoom out / zoom in / hide timeline).
• fixed the broken timeline refresh calls (stale renderTimeline usage).
• fixed insert/delete frame handlers using canvas contexts correctly.
• strengthened hide/show wiring so clicks on nested icon elements still work.
• added body-level collapse handling so timeline hide/show is reliable with current dom structure.