v1.0.60 — UI/UX fixes

FIXED: Burger menu now fully covers map controls
- Sheet drawer z-index raised above all map floating buttons (z-[2100])
- Map FABs, zoom controls, and filter pills no longer punch through the open menu

IMPROVED: My Stash desktop layout
- Sidebar expanded to 300px with real visual weight
- Inventory card: large item count, est. sats value, per-type stats row (Wishlist / For Sale / To Trade)
- Clickable category breakdown bars act as filter shortcuts
- Marketplace CTA card: sell/trade count badges, gradient button
- Quick Add buttons (Add to Stash / Add to Wishlist) moved into sidebar
- Grid layout: 2/3/4 columns (md/lg/xl) — no more awkward stretched single-item rows
- Bigger, more purposeful empty states