feat(test): add end-to-end live API test suite (DIS-73)

Adds comprehensive e2e tests gated behind LIVE_TEST=true that:
- Test all 8 command domains via SDK and CLI shell execution
- Validate all 3 output formats (json, table, toon)
- Verify parity between SDK responses and direct REST API calls
- Test error handling (invalid API key, non-existent slugs, missing key)
- Generate JSON report with pass/fail per command x format

Co-Authored-By: Chris K <ckorhonen@gmail.com>

Author: devin-ai-integration[bot]