chore(evals): comprehensive cleanup, documentation, and test infrastructure improvements

Documentation:
- Add ARCHITECTURE.md with comprehensive system review
- Add GETTING_STARTED.md for new users
- Add DOCUMENTATION_CLEANUP.md tracking cleanup changes
- Add SCRIPTS_ORGANIZATION.md documenting script reorganization
- Remove outdated docs (TESTING_CONFIDENCE.md, TEST_REVIEW.md, SESSION_STORAGE_FIX.md)
- Update README files with current information

Script Organization:
- Move 12 scripts from framework root to organized directories:
  - scripts/debug/ (4 files): Session debugging tools
  - scripts/test/ (6 files): Test execution scripts
  - scripts/utils/ (2 files): Utility scripts
- Add comprehensive scripts/README.md with usage examples

Test Infrastructure:
- Add 5 new context loading tests for openagent
- Add result-saver.ts for test result persistence
- Add interactive results dashboard (index.html)
- Add error-handling.test.ts for framework testing
- Add result-saver.test.ts with comprehensive unit tests

Evaluator Improvements:
- Enhance context-loading-evaluator with better detection
- Update run-sdk-tests.ts with improved result handling

Agent Configuration:
- Add .opencode/agent/AGENT.md for agent definition

Test Utilities:
- Add test-agent-manual.mjs for manual testing
- Update test_tmp/README.md with usage guidelines

This commit consolidates multiple improvements:
- Better organization (scripts, docs)
- Improved testing infrastructure
- Comprehensive documentation
- Cleaner codebase structure