fix(links): prevent spam link submissions and handle React keys corre…

[Strategosky]

This PR removes spam/test submissions and implements safeguards to prevent them in the future. It also fixes a React list key warning.

Key Changes:

1. Database Cleanup

• Removed existing spam documents (with titles "q" and "Test") from the live Firestore collection.

2. Spam Submission Prevention

• Added form validation to block new link contributions containing lazy/spam titles like "q" or "test" (case-insensitive).

3. Display-time Filter

• Added a frontend filter to ensure any records matching these spam titles are hidden from the UI.

4. React List Key Fix

• Mapped the unique Firestore document id into the data array, resolving React console warnings caused by item.id being undefined.