Add Missing Test Files for 11 Themes in Codebase

[ChetanSenta]

Description

Fixes #8321

Pillar

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

Visual Preview

No visual change — pure test additions.

What this PR does

21 of 32 real themes in lib/svg/themes.ts have a dedicated test file in
lib/svg/themes/ (hex validity, design-spec match, SVG output check,
WCAG AA contrast). 11 didn't: cyberpunk, cyberpunk_neon, default,
enterprise, github, glacier, india, monokai, retro-terminal,
solarized_light, tokyonight. Added the missing 11, following the
exact existing convention. All 11 themes' real hex values were confirmed
in advance to already pass the WCAG AA contrast check, so no production
color values needed to change.

Checklist before requesting a review:

• I have read the CONTRIBUTING.md file.
• I have tested these changes locally.
• I have run npm run format and npm run lint locally and resolved all errors.
• My commits follow the Conventional Commits format.
• I have made sure that I have only one commit to merge in this PR.

[retenta-bot]

This pull request addresses the issue of missing test files for several themes, which is crucial for maintaining code quality and ensuring that all themes are properly validated. It follows the existing conventions and confirms that the themes meet the necessary accessibility standards. This aligns with past decisions made to implement and document themes accurately in the codebase. Thank you for your contribution, and I look forward to your updates!

[github-actions]

📦 Next.js Bundle Size Report (Gzipped Sizes)

✨ No significant bundle size changes detected.

📊 Summary of Totals

Category	PR Size	Base Size	Difference
Total JS	4052.50 KB	4052.50 KB	0 B
Total CSS	338.94 KB	338.94 KB	0 B

[Aamod007]

Adding missing test files for 11 themes across the codebase — good coverage improvement. CI pending, once green ready to merge.

Labels: level:intermediate (11 files), quality:clean, type:testing, mentor:Aamod007

[Aamod007]

Re-reviewing after noting the only CI failure is Vercel authorization (not code-related). All other checks (Format · Lint · Typecheck · Test, Production Build, CodeQL) pass. Approving — the Vercel deploy auth is a repo-level config issue, not a code problem.