test(svg): add layout massive scaling coverage

[mayank200529]

Description

Fixes #4404

Added a dedicated test suite for lib/svg/layout.ts covering massive data sets and extreme scaling scenarios.

Changes

• Added coverage for very large calendar datasets
• Verified latest 14-week window behavior under heavy input sizes
• Tested coordinate stability and uniqueness across dense layouts
• Validated scaling with extreme contribution counts and LoC values
• Added performance checks to ensure layout computation remains efficient

Pillar

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

Visual Preview

N/A (test-only change)

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(themes): ..., fix(calculate): ...).
• 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 (not applicable for test-only changes).
• (Recommended) I joined the CommitPulse Discord community for contributor discussions, mentorship, and faster PR support.

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[github-actions]

🚨 Hey @mayank200529, the CI Pipeline is failing on this PR and it has been marked as status:blocked.

Please fix the issues before this can be reviewed. Here's how:

1. Run checks locally before pushing:

npm run format:check   # Check Prettier formatting
npm run lint           # Run ESLint
npm run typecheck      # TypeScript type check
npm run test           # Run unit tests (Vitest)
npm run build          # Verify production build passes

2. Auto-fix common issues:

npm run format         # Auto-fix formatting with Prettier
npm run lint -- --fix  # Auto-fix lint errors where possible

3. Check the full failure log here:
👉 View CI Run

Once you push a fix and the CI passes, the status:blocked label will be removed automatically. 💪

[Aamod-Dev]

Thanks for the PR. I've reviewed the changes and they look good to me.

The test coverage added here looks comprehensive and well-structured. It definitely improves the reliability of the system.

No concerns from my end. Approved.

[Aamod-Dev]

Thanks for the PR. I've reviewed the changes and they look good to me.

The test coverage added here looks comprehensive and well-structured. It definitely improves the reliability of the system.

Everything looks good. Approving this now.

[Aamod-Dev]

Thanks for the contribution. I've taken a look at the changes and everything seems to align with what we need here.

Looks solid. I'll go ahead and approve.

[github-actions]

🎉 Congratulations @mayank200529! Your PR has been successfully merged. 🚀

Thank you for contributing to CommitPulse. Your work helps us build a better tool for the community.

⚠️ Important for GSSoC Contributors:
You are strictly advised to join our Discord Server as it is mandatory for all GSSoC participants. All important announcements, point claims, and community discussions happen there.

Keep building! 💻✨

[Aamod-Dev]

Review Summary
Removed duplicate category labels (quality:exceptional, ype:feature) to adhere to the strict rule of exactly one label per category (retained quality:clean, ype:testing).