feat: styling polish, command palette, breadcrumbs, activity feed, export, sort, clipboard

- 40+ styling fixes across all 11 pages (consistent padding, titles, empty states, date formatting)
- Command Palette (Ctrl+K) with 11 nav items + 3 actions
- Breadcrumbs with hash-based path detection and mobile truncation
- Activity Feed component with 11 color-coded action icons and 30s auto-refresh
- ExportButton (CSV) on Purchases, Audit, Users pages
- SortableHeader with 3-state toggle on Purchases and Audit pages
- copyToClipboard utility with navigator.clipboard + fallback
- Notification badge on Purchases sidebar item (pending count)
- Connection status indicator in sidebar footer
- Removed dynamic imports from page.tsx (reduces memory)
- Disabled Prisma query logging (reduces memory)
- All components verified: named exports, @/ prefix, hash navigation, sonner toasts

src/lib/db.ts

@@ -7,7 +7,7 @@ const globalForPrisma = globalThis as unknown as {
 export const db =
   globalForPrisma.prisma ??
   new PrismaClient({
-    log: ['query'],
+    log: ['error'],
   })
 
 if (process.env.NODE_ENV !== 'production') globalForPrisma.prisma = db