[FEAT] Add PR status donut chart (open/merged/closed) to PRMetrics widget

[Priyanshu-byte-coder]

Summary

PRMetrics shows PR counts but no visual breakdown of open vs merged vs closed PRs. A donut chart would make the distribution immediately clear.

Expected Behaviour

A donut/pie chart showing:

• Open PRs (accent color)
• Merged PRs (green)
• Closed without merge (red/muted)

With a legend below. Total PR count in the center.

Implementation Notes

• Recharts PieChart is already a dependency — use it
• Data: { open, merged, closed } from existing PR metrics API response
• Center label: '{total} PRs'
• Hover tooltip showing count and percentage
• No hardcoded colors — use var(--accent), emerald-500, var(--muted-foreground)

GSSoC Info

• Difficulty: Intermediate — 35 pts
• Area: UI / Data Visualization

[26Naitik]

Hi @Priyanshu-byte-coder,

I would like to work on this issue under GSSoC'26.
I have experience working on DevTrack dashboard UI/features and would love to contribute to this enhancement.

Could you please assign it to me?

[diksha12345612]

Hi @Priyanshu-byte-coder
I would like to work on this issue under GSSoC'26.
I have experience working on DevTrack dashboard UI/features and would love to contribute to this enhancement.

Could you please assign it to me?

[mallya-m]

Hi @Priyanshu-byte-coder!
I'd love to take this on under GSSoC '26.

Having already worked on TopRepos (#303, #306) I'm comfortable with
how the widgets consume API data here.
The PR counts (open/merged/closed) are already returned by /api/metrics/prs so this needs no new endpoint —
just a PieChart from Recharts wired to existing data. I'll keep it
consistent with the card styles used across the dashboard.

Could you please assign this to me?
GitHub: github.com/mallya-m