update nav for garden, add icons and animations

Created by: jedmund

Summary

• Reorder nav items: Garden after Labs in desktop, before About in dropdown
• Add leaf sway hover animation for Garden nav item
• Update garden SVG with stem, redraw play icon with rounder tips
• Extract heart SVG from inline, add checkbox-checked and play-circle icons
• Update category icons
• Fix NowPlayingBar width to match wider nav

Test plan

• Garden appears in correct position in both navs
• Leaf sway animation plays on hover
• NowPlayingBar matches SegmentedController width
• Heart button renders correctly from extracted SVG