Fix language chart empty-state crash

[saurabhhhcodes]

Description

Fixes #125.

This PR prevents the dashboard from crashing when LanguageChart receives an empty language array, which can happen for users with no public repo language data or sparse GitHub profiles. It adds a stable empty-state card that keeps the existing Top Languages layout and adds regression coverage for both empty and populated data.

Pillar

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

Visual Preview

No screenshot attached; this is a dashboard crash fix. Empty language data now renders the existing card with No language data found instead of throwing on languages[0].

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. N/A: no README change needed.
• I have started the repo. N/A for this component-level crash fix; static checks were run locally.
• 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). N/A: no SVG output changed.
• (Recommended) I joined the CommitPulse Discord community for contributor discussions, mentorship, and faster PR support.

Testing

• npm run typecheck ✅
• npm run lint -- components/dashboard/LanguageChart.tsx components/dashboard/LanguageChart.test.tsx ✅
• npm run format:check -- components/dashboard/LanguageChart.tsx components/dashboard/LanguageChart.test.tsx ✅
• git diff --check ✅

Local Environment Notes

• Focused Vitest could not start in this Codex macOS sandbox because Rolldown’s native optional binding failed code-signature validation (ERR_DLOPEN_FAILED).
• next build is blocked locally by the same macOS native SWC code-signature issue plus no global npm fallback path.

[vercel]

Someone is attempting to deploy a commit to the jhasourav07's projects Team on Vercel.

A member of the Team first needs to authorize it.

[github-actions]

👋 Hey @saurabhhhcodes, it looks like you didn't use our PR template!

The section ## Description is missing from your PR description.

Please update your PR description to include all required sections so we can review this properly:

• ## Description — What does this PR do? Which issue does it fix?
• ## Pillar — Which contribution pillar does this fall under?
• ## Checklist — Have you ticked off the quality checklist?

You can find the full template in CONTRIBUTING.md. Just edit your PR description and the needs-details label will be removed automatically. 🙌

[github-actions]

👋 Hey @saurabhhhcodes, welcome to CommitPulse! 🎉

Thanks for opening your first pull request — this is a big deal and we appreciate the effort!

While you wait for a review, please double-check:

• ✅ You've read the CONTRIBUTING.md checklist
• ✅ npm run lint, npm run format, and npm run test all pass locally
• ✅ Your PR has a visual preview if it touches any SVG output
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[saurabhhhcodes]

Small GSSoC label note: if this fix is accepted, could you please add gssoc:approved, level:beginner, quality:clean, and type:bug? The PR fixes the assigned crash issue #125 and includes a regression test plus passing type/lint/format checks.

[saurabhhhcodes]

Quick CI note: I checked the failing status after updating the PR template. The only visible failure is Vercel reporting Authorization required to deploy, which needs project/team authorization from the maintainer side. The code-side local checks I could run are still green:

• npm run typecheck
• npm run lint -- components/dashboard/LanguageChart.tsx components/dashboard/LanguageChart.test.tsx
• npm run format:check -- components/dashboard/LanguageChart.tsx components/dashboard/LanguageChart.test.tsx
• git diff --check

Please re-run/authorize the Vercel preview when convenient.

[JhaSourav07]

@saurabhhhcodes

npm run test is failing