fix: Resolve build errors with border color and import paths

- Add missing --border CSS variable for light and dark mode
- Add border color to Tailwind config using hsl(var(--border))
- Fix import paths in sidebar.tsx (@/hooks/ instead of @/components/hooks/)
- Fix import path in toaster.tsx (@/hooks/ instead of @/components/hooks/)

These fixes ensure npm run dev / npm run build work out of the box.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tailwind.config.ts

@@ -12,6 +12,7 @@ const config: Config = {
   		colors: {
   			background: 'var(--background)',
   			foreground: 'var(--foreground)',
+  			border: 'hsl(var(--border))',
   			sidebar: {
   				DEFAULT: 'hsl(var(--sidebar-background))',
   				foreground: 'hsl(var(--sidebar-foreground))',