feat(frontend): optimize contributor avatar delivery (JhaSourav07#616)

## Description

Fixes JhaSourav07#555 

This PR improves contributor avatar rendering by introducing responsive
image optimization and layout stability enhancements, addressing
Lighthouse warnings related to oversized image delivery and cumulative
layout shift.

Previously, avatars were served at full resolution regardless of display
size, leading to unnecessary payload overhead and suboptimal performance
metrics on audit tools.

### Key Improvements

* Responsive avatar sizing using GitHub’s `s` query parameter
* Explicit `width` and `height` attributes to ensure layout stability
(CLS prevention)
* Lazy loading enabled for offscreen image deferral
* Consistent square rendering using `aspect-square`
* Maintains existing UI fidelity while improving performance efficiency

### Before

```jsx
<img
  src={user.avatarUrl}
  alt={user.name}
  className="w-full h-full object-cover"
/>
```

### After

```jsx
<img
  src={`${user.avatarUrl}${user.avatarUrl.includes('?') ? '&' : '?'}s=120`}
  alt={user.name || 'Contributor Avatar'}
  width={96}
  height={96}
  loading="lazy"
  className="w-full h-full aspect-square object-cover"
/>
```

---

## Impact

* Eliminates oversized image delivery warnings in Lighthouse
* Reduces unnecessary network payload for avatar assets
* Improves visual stability via explicit intrinsic sizing
* Enhances mobile performance and bandwidth efficiency
* Aligns with modern frontend performance best practices

---

## Pillar

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

---

## Visual Preview
<img width="1038" height="740" alt="Screenshot 2026-05-27 154740"
src="https://github.com/user-attachments/assets/0bb572b3-deb5-4ed3-8696-4d0631413516"
/>


Lighthouse comparison screenshots included demonstrating:

* Reduced performance warnings
* Improved layout stability (CLS)
* Cleaner image optimization audit results

---

## Checklist before requesting a review

* [x] I have read `CONTRIBUTING.md`
* [x] I have validated changes locally
* [x] I have run `npm run format` and `npm run lint` with no errors
* [x] My commit follows Conventional Commits standards
* [x] PR contains a single, atomic commit
* [x] Changes maintain CommitPulse’s premium UI/UX standards

---

Author: JhaSourav07

components/dashboard/ProfileCard.tsx

@@ -27,7 +27,14 @@ export default function ProfileCard({ user, exportData }: ProfileCardProps) {
           <div className="relative mb-5">
             <div className="w-24 h-24 rounded-full overflow-hidden border border-black/10 dark:border-[rgba(255,255,255,0.12)]">
               {/* eslint-disable-next-line @next/next/no-img-element */}
-              <img src={user.avatarUrl} alt={user.name} className="w-full h-full object-cover" />
+              <img
+                src={`${user.avatarUrl}${user.avatarUrl.includes('?') ? '&' : '?'}s=120`}
+                alt={user.name || 'Contributor Avatar'}
+                width={96}
+                height={96}
+                loading="lazy"
+                className="w-full h-full aspect-square object-cover"
+              />
             </div>
             {user.isPro && (
               <span className="absolute -bottom-1 -right-1 text-[9px] font-bold bg-black text-white dark:bg-white dark:text-black px-1.5 py-0.5 rounded-full tracking-wide">