fix(TopRepos): show repo description as native tooltip on name hover (#214)

[Jyoti1-pog]

Summary

Fixes #214 — TopRepos listed repository names but never surfaced the
description the GitHub API already returns. Hovering a repo name now shows
its description as a native browser tooltip. Repos with no description
(null or "") correctly show no tooltip at all.

Changes

• src/components/TopRepos.tsx — added description: string | null to
  the Repo type; set the repo name link's
  title={repo.description || undefined}.
• src/app/api/metrics/repos/route.ts — threaded description through
  the GitHub search response type, the repoMap projection, the
  RepoSummary type, and the multi-account mergeRepoCommits merge. The
  field was being dropped at every step of the API → component pipeline.

Using || undefined (not "") makes React omit the title attribute
entirely when there is no description, so no empty tooltip renders.

Verification

Confirmed against the live GitHub API that search/commits returns
repository.description, and verified end-to-end on the dashboard that a
repo with a description shows the tooltip while a repo with a null
description shows none.

Tooltip shows on hover (repo with a description):

No tooltip (repo with null/empty description):

Note

The repo name link previously had title={repo.name} (full org/repo
path on hover). An element can carry only one title, and the issue
explicitly specifies title={repo.description || undefined} on the name
element, so that prior tooltip is now replaced by the description — this is
the behaviour the issue asks for.

Closes #214

[vercel]

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

A member of the Team first needs to authorize it.

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