test(ourteam): add comprehensive unit tests for TeamMemberCard (Vitest + RTL)

[VetteIT]

Description

Adds a comprehensive unit test suite for the TeamMemberCard component using Vitest + React Testing Library.
Tests are co-located next to the component and focus on behavior (not styles), including avatar rendering/fallback, GitHub link attributes, role chip labeling, and click behavior for roles with/without links.

Closes #116

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What change does this PR introduce?

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• CI/CD (updates related to the CI/CD process)
• Chore (miscellaneous tasks that do not fall into the above options)

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What is the proposed approach?

• Testing strategy: Vitest + React Testing Library with co-located tests.
• Mocks:
  • react-i18next mocked to return default strings for stability.
  • useIsDesktop mocked to validate both desktop and mobile code paths.
• Behavior covered:
  • Renders avatar <img> when avatarUrl is provided; hides <img> on onError (fallback behavior).
  • Falls back to icon when avatarUrl is absent.
  • Displays member name.
  • Renders GitHub link with correct href, target="_blank", and rel="noopener noreferrer".
  • Renders role chips:
    • Two-line label when project is present.
    • Single-line label when project is absent.
  • Clicking a role with link calls window.open(link); clicking a role without link is a no-op.
  • Supports multiple roles.
• Scope: Tests only; no production code changes.

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Checklist:

• The commit message follows our adopted guidelines
• Testing has been done for the change(s) added (for bug fixes/features)
• Relevant comments/docs have been added/updated (for bug fixes/features)