VSN-2269: Redesign dashboard layout with dark glass sidebar, updated header/footer and nav components

Summary

• Redesign the full dashboard shell: sidebar, header toolbar, footer, auth page, and
  navigation components
• Apply dark glassmorphism sidebar with soft gradient backgrounds, lucide-react icons
  replacing MUI icons
• Modernize header with grouped icon strip layout (quick actions / navigation / communication / account)

Changes

Dashboard Layout (src/layouts/dashboard/)

• index.tsx — Restructure layout to use sidebar width constants, cleaner responsive toggle
  logic
• nav-vertical.tsx — Dark glass sidebar with gradient background (hsl(240 24% 9%) to hsl(248 43% 16%)), frosted glass effect, soft glow accents, smooth open/close transitions
• nav-mini.tsx — Compact sidebar variant with matching dark glass styling, icon-only mode
  with tooltips
• header.tsx — Replace flat header with hsl(248 80% 97%) tinted AppBar, grouped icon strip
  with LineSep gradient separators between action groups (quick actions → navigation →
  communication → account)
• footer.tsx — Replace MUI AppBar/Toolbar/Typography with a clean Tailwind element
• main.tsx — Adjust main content padding to align with new sidebar widths

Layout Config

• config-layout.ts — Update sidebar width constants for new design

Common Layout Components (src/layouts/common/)

• account-popover.tsx — Replace MUI icons with lucide-react (User, KeyRound, FolderOpen,
  LogOut, etc.), refine avatar ring with primary color glow, restructured menu items with
  smooth hover transitions
• notification-popover.tsx — Redesign notification panel with glassmorphism card styling,
  category tabs, improved empty state
• menu-popover.tsx — Updated popover styling with refined border radius and shadows
• searchbar.tsx — Enhanced search bar with updated styling and transitions
• nav-toggle-button.tsx — Updated sidebar toggle button design

Auth Layout

• classic.tsx — Full redesign: animated particle network canvas background, ambient gradient glows, dark theme login page with frosted glass card

Form Layout

• form-container.tsx — Updated MUI form container styling for consistency

Nav Section Components (src/shared/components/nav-section/vertical/)

• nav-item.tsx — Refined nav item styling with active state indicators, hover transitions,
  icon/text color updates
• nav-list.tsx — Simplified nav list logic
• nav-section-vertical.tsx — Updated section header and group styling

Loading Screens (src/shared/components/loading-screen/)

• loading-screen.tsx — Updated loading animation design
• splash-screen.tsx — Enhanced splash screen with new branding animation