Resolve "Feat: Intern Search (Corpus Service + InternSearch Component)"

Closes #4 (closed)

MR: Add Intern Name Search and InternSearch Component

Summary

This MR adds name-based intern search functionality to the corpus service and introduces a standalone InternSearch React component. The component allows users to search interns and add them to a local list with duplicate prevention.

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Changes

• Added searchInternsByName to corpus service with live + mock support
• Extended mock intern data for realistic search results
• Exported new search function from service index
• Introduced InternSearch component with:
  • 300ms debounced search
  • Loading indicator
  • Empty and no-result handling
  • Local intern list with duplicate prevention

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Scope

• corpusService.ts
• index.ts
• InternSearch.tsx

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Testing

• npx tsc --noEmit
• Manual verification of:
  • Debounced search behavior
  • Add / Added state handling
  • Empty query behavior

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Notes

• No external libraries used
• No routing or global state introduced
• Does not impact existing workflows
• Component is fully reusable and UI-ready