[IMP] Implement Auth Integration, Design System, and Full Portal UI Overhaul

[akrs-code]

Summary

Completed authentication integration, enforced a glassmorphism design system across all portals, introduced a centralized DataTable, and refactored admin, seller, and buyer components into a feature-based module structure.

Changes Introduced

• Feature/Enhancement
• Bug Fix
• Refactor
• Documentation
• Other:

Change Description:

1. Finished login and register flow with auth/authorization integration and shared verification.
2. Updated admin, seller, and buyer pages and components for consistency.
3. Updated cart context and core layout, API services, and shared components.
4. Integrated React Table and implemented a centralized DataTable component.
5. Reorganized admin and seller components into feature-based module directories.
6. Centralized UI components and design system tokens.
7. Applied glassmorphism aesthetic across buyer, seller, and admin portals.
8. Modernized shared layouts and auth pages.
9. Standardized data tables with minimum column and single-row enforcement.
10. Centralized dialog, confirm-dialog, and notification components.
11. Implemented dynamic multi-image display and upload for products.
12. Refined admin analytics, seller dashboard/inventory, and buyer checkout/orders views.
13. Updated main app routing and global header.
14. Updated dependencies.

Testing Instructions

1. Log in and register as each role — confirm auth flow works end to end.
2. Open admin portal — confirm analytics, tables, and panels render consistently.
3. Open seller portal — confirm dashboard and inventory views follow design system.
4. Open buyer portal — confirm checkout, orders, and marketplace display correctly.
5. Upload multiple product images — confirm dynamic image display and upload work.
6. Trigger a dialog and confirm-dialog — confirm centralized components render correctly.

Checklist

• Code compiles without errors
• Tests added/updated
• Linting/formatting checks passed
• Documentation updated (if needed)
• No sensitive data committed