feat(navbar): add direct anchor link to customization studio (JhaSourav07#945)

## Description

Fixes JhaSourav07#888 

This PR introduces a "Customization Studio" shortcut link directly to
the top navigation bar and responsive mobile drawer menu. This ensures
that users don't have to scroll all the way to the bottom of the landing
page to discover or access the interactive fine-tuning tool, improving
overall feature engagement and user experience.

Key changes:
- Centralized the link configuration within the `NAV_LINKS` array inside
`navbar.tsx`.
- Updated desktop and mobile mapping loops to handle internal section
smooth-scrolling links vs external target links safely.
- Added matching `id="customization-studio"` to the root `<motion.div>`
element of `CustomizeCTA.tsx` to serve as a precise scrolling anchor
point.

## Pillar

- [ ] 🎨 Pillar 1 — New Theme Design
- [ ] 📐 Pillar 2 — Geometric SVG Improvement
- [ ] 🕐 Pillar 3 — Timezone Logic Optimization
- [x] 🛠️ Other (Bug fix, refactoring, docs)

## Visual Preview
- Added a new functional text link in the header row.
- Clicking smoothly scrolls the layout down to the target block
container.
<img width="1280" height="832" alt="Screenshot 2026-05-28 at 5 47 26 PM"
src="https://github.com/user-attachments/assets/522c5774-689e-4aab-8923-22bbccbbd318"
/>


## Checklist before requesting a review:

- [x] I have read the `CONTRIBUTING.md` file.
- [x] I have tested these changes locally
(`localhost:3000/api/streak?user=YOUR_USERNAME`).
- [x] I have run `npm run format` and `npm run lint` locally and
resolved all errors (CI will fail otherwise).
- [x] My commits follow the Conventional Commits format (e.g.,
`feat(themes): ...`, `fix(calculate): ...`).
- [ ] I have updated `README.md` if I added a new theme or URL
parameter.
- [x] I have started the repo. (This means a lot to us ❤️)
- [x] I have made sure that i have only one commit to merge in this PR.
- [x] The SVG output matches the CommitPulse "premium quality" aesthetic
standard (no raw elements, smooth animations, correct fonts)
- [x] (Recommended) I joined the CommitPulse Discord server for faster
collaboration, mentorship, and PR support.

Author: JhaSourav07

app/components/CustomizeCTA.tsx

@@ -6,6 +6,7 @@ import { motion } from 'framer-motion';
 export function CustomizeCTA() {
   return (
     <motion.div
+      id="customization-studio"
       initial={{ opacity: 0, y: 20 }}
       animate={{ opacity: 1, y: 0 }}
       transition={{ duration: 0.5, ease: 'easeOut' }}

app/components/navbar.tsx

@@ -14,9 +14,15 @@ function GithubMark() {
 }
 
 const NAV_LINKS = [
+  {
+    label: 'Customization Studio',
+    href: '#customization-studio',
+    isExternal: false,
+  },
   {
     label: 'GitHub Repo',
     href: 'https://github.com/JhaSourav07/commitpulse',
+    isExternal: true,
   },
 ];
 
@@ -131,11 +137,11 @@ export default function Navbar() {
                 <a
                   key={link.href}
                   href={link.href}
-                  target="_blank"
-                  rel="noopener noreferrer"
+                  target={link.isExternal ? '_blank' : undefined}
+                  rel={link.isExternal ? 'noopener noreferrer' : undefined}
                   className="inline-flex items-center gap-2 rounded-xl border border-white/15 bg-white/5 px-4 py-2 text-sm font-medium text-white/90 transition hover:border-white/45 hover:bg-white/10"
                 >
-                  <GithubMark />
+                  {link.isExternal && <GithubMark />}
                   {link.label}
                 </a>
               ))}
@@ -159,12 +165,12 @@ export default function Navbar() {
                   <li key={link.href}>
                     <a
                       href={link.href}
-                      target="_blank"
-                      rel="noopener noreferrer"
+                      target={link.isExternal ? '_blank' : undefined}
+                      rel={link.isExternal ? 'noopener noreferrer' : undefined}
                       onClick={() => setOpen(false)}
                       className="inline-flex w-full items-center gap-2 rounded-xl border border-white/15 bg-white/5 px-4 py-2 text-sm font-medium text-white/90 transition hover:border-white/45 hover:bg-white/10"
                     >
-                      <GithubMark />
+                      {link.isExternal && <GithubMark />}
                       {link.label}
                     </a>
                   </li>