SFMS: Design mobile pattern for map layers and legend controls

**The task**

Design focused on wireframing. The current layers/legend interface is a floating card designed for desktop but takes up a large portion of the screen. Design a mobile-native equivalent (perhaps a bottom-sheet pattern consistent with existing mobile drawer conventions).

**Acceptance Criteria**
- [ ] Mobile wireframes produced showing the layers/legend control in its collapsed and expanded states on mobile
- [ ] Pattern reuses existing mobile drawer/sheet conventions already established in the component library
- [ ] Mobile wireframes ready for prototype build

**SME/User Contact**

Any SFMS map user on a mobile device needing to toggle or interpret map layers.