Research: Test Anthropic API authentication with Desktop tokens

[UncleTallest]

Goal: Verify that Claude Desktop tokens work with the Messages API.

Depends on: #1 (auth token research)

Tasks:

• Write test script to authenticate with found tokens
• Test basic API calls (create message, get response)
• Document rate limits and quota behavior
• Test error handling (invalid token, expired token)
• Verify streaming responses work

Success criteria:

• Can authenticate successfully with Desktop tokens
• Basic conversation flow works
• Error cases handled gracefully

Output: Working proof-of-concept in research/api-testing/