feat:-Refactor Full TypeScript Migration + Architecture Modernization

Summary

This MR completes the architectural modernization of the Codonix frontend by converting the entire codebase to TypeScript and setting up a clean, scalable project structure.

Changes

1. refactor — JSX → TSX Full Conversion

• Renamed all 36 .jsx files (components + pages) to .tsx
• Includes all files under src/components/, src/pages/, and src/pages/Services/
• Reorganized components into a structured folder hierarchy:
  • src/components/common/ — shared page-level components
  • src/components/layout/ — Navbar, Footer, ScrollToTop
  • src/components/ui/ — reusable UI primitives

2. fix — PostCSS / Tailwind v4 Compatibility

• Installed @tailwindcss/postcss package required by Tailwind CSS v4
• Updated postcss.config.js to use '@tailwindcss/postcss' instead of the deprecated tailwindcss plugin key
• Resolves the Cannot find module 'tailwindcss' PostCSS error introduced by the dev branch rebase

3. feat — Footer Light Mode Redesign

• Applied a sky-blue pastel gradient background to the footer in light mode (#f5fbff → #d9f1ff → #b4e2f9)
• Added full light mode CSS overrides to mirror the dark theme's layout exactly:
  • Navy brand heading, blue-toned section headings & links
  • Glassmorphism "Genomics Intelligence" badge
  • Circular social icon buttons with hover lift effect
  • Centered gradient divider line in the footer bottom bar

4. feat — New Architecture Files

• Added src/context/useAppStore.ts — Zustand global state for theme management
• Added src/api/client.ts — Axios API client setup
• Added src/styles/ — shared CSS files for consistent theming
• Added tailwind.config.js — Tailwind configuration

Testing

• ✅ npx tsc --noEmit — zero TypeScript errors
• ✅ npm run build — production build successful
• ✅ Dev server runs cleanly with no PostCSS or module resolution errors