Add adaptive UI testing demo with Amazon Nova Act

[marakere]

Issue #, if available: N/A

Description of changes:

This PR adds a complete demo project demonstrating AI-powered browser automation using Amazon Nova Act - testing applications the way humans interact with them, through natural language instructions and visual context rather than hardcoded DOM selectors.

What's included:

• Sample Student Information System web app (sample-app/)
• Nova Act test cases using natural language actions (nova-act-tests/)
• Playwright test cases using selector-based approach (playwright-tests/)
• Three-phase demo scripts simulating a realistic development cycle:
  • Phase 1: Baseline - both frameworks pass on original UI
  • Phase 2: Structural refactoring (changed IDs, labels, field order) - Nova Act adapts automatically, Playwright needs selector updates
  • Phase 3: New features (email + GPA fields) - both need updates, Nova Act's natural language approach simplifies additions
• Setup script, restore script, and phase runner scripts
• Supports AWS IAM and API key authentication

Key takeaway for reviewers:
Nova Act interprets instructions like "Click the save button" through visual context and natural language understanding, complementing selector-based testing by providing resilience during UI evolution. Phase 2 demonstrates this - the same Phase 1 Nova Act test passes after refactoring without any modifications.

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