refactor(format): add pluralize helper and replace inline plural ternaries

[Dexterity104]

Summary

Adds a pluralize helper to src/utils/format.ts and replaces inline ${n} thing${n !== 1 ? 's' : ''} ternaries at the sites most prone to plural typos. The helper handles regular plurals ('commit' → 'commits') and takes an explicit second form for irregular ones (pluralize(n, 'bounty', 'bounties')).

export const pluralize = (
  count: number,
  singular: string,
  plural?: string,
): string =>
  count === 1 ? `${count} ${singular}` : `${count} ${plural ?? `${singular}s`}`;

No behavior change. Rendered output is byte identical at every call site, including the 0 things and 1 thing edge cases.

Call sites updated:

• src/components/ContributionHeatmap.tsx
• src/components/miners/MinerPrScoreDetail.tsx
• src/pages/dashboard/views/FeaturedWorkRepoCard.tsx
• src/pages/RepositoriesPage.tsx
• src/pages/RepositoryDetailsPage.tsx
• src/pages/search/SearchPage.tsx
• src/utils/repoConfig.ts

Sites where the count and noun appear in separate positions (split by an adjective or rendered as a fraction) were left alone to avoid restructuring the surrounding markup.

Related Issues

N/A

Type of Change

• Bug fix
• New feature
• Refactor
• Documentation
• Other (describe below)

Screenshots

Not applicable. Pure logic refactor with no visual change.

Checklist

• New components are modularized/separated where sensible
• Uses predefined theme (e.g. no hardcoded colors)
• Responsive/mobile checked
• Tested against the test API
• npm run format and npm run lint:fix have been run
• npm run build passes
• Screenshots included for any UI/visual changes