feat(waa): refactor CLI and fix Python 3.9 compatibility (#14)

- Refactor CLI from 6800 to ~1300 lines with flat command structure
- Add analyze command to parse and summarize benchmark results
- Add --num-tasks flag to limit number of tasks to run
- Fix Python 3.9 compatibility by copying Python from vanilla WAA image
  (fixes transformers 4.46.2 compatibility with GroundingDINO)
- Add coverage and analysis artifacts to .gitignore

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: abrichr

.gitignore

@@ -59,6 +59,16 @@ demos/
 # Pytest cache
 .pytest_cache/
 
+# Coverage files
+.coverage
+.coverage.*
+htmlcov/
+
+# Analysis/debug artifacts
+cli_analysis.json
+dead_code_candidates.json
+segmentation_output/
+
 # Internal documentation (not for public repo)
 docs/internal/
 docs/private/