fix the issue of dowloading badge as PDF

[Alishaa-987]

Description

Fixes #7981

What changed:
Implemented the complete "Download PDF" functionality for the CommitPulse badge.

Previously, downloading the badge as a PDF was either broken or not implemented. I built out the full export pipeline to ensure users can export their 3D isometric stats seamlessly into a high-quality PDF.

Implementation details:

• Created a robust SVG-to-Canvas rendering pipeline using standard DOM APIs.
• Handled the complex CSS extraction for the .cp-bg-fill, .cp-text-fill, and .cp-accent-fill classes so the PDF matches the chosen theme perfectly.
• Injected animation overrides (animation: none !important, transform: scaleY(1)) into the capture process so the HTML Canvas doesn't accidentally capture an invisible frame at 0s during the 3D tower entrance animation.
• Integrated jspdf to properly dimension and export the final canvas output into a downloadable .pdf file.

Pillar

• 🎨 Pillar 1 — New Theme Design
• 📐 Pillar 2 — Geometric SVG Improvement
• 🕐 Pillar 3 — Timezone Logic Optimization
• 🛠️ Other (Feature / Core Functionality)

Visual Preview

Checklist before requesting a review:

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

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[github-actions]

📦 Next.js Bundle Size Report (Gzipped Sizes)

Asset	PR Size	Base Size	Difference	Status
static/chunks/1144-[hash].js	2.15 KB	-	+2.15 KB (++100%)	🆕 New
static/chunks/2705-[hash].js	5.87 KB	-	+5.87 KB (++100%)	🆕 New
static/chunks/6420-[hash].js	-	7.82 KB	-7.82 KB (-100.00%)	🗑️ Deleted
static/chunks/app/page-[hash].js	20.60 KB	19.64 KB	+0.96 KB (+4.89%)	🔴 Regression

📊 Summary of Totals

Category	PR Size	Base Size	Difference
Total JS	3913.18 KB	3910.49 KB	+2.69 KB (+0.07%)
Total CSS	326.92 KB	326.92 KB	0 B