Polish public launch documentation and CLI help

[antoinezambelli]

Summary

• explain the pragmatic upstream-regression bridge without overstating native-agent equivalence
• make README links safe when rendered as the PyPI long description
• demonstrate and bound the durable audit evidence captured for each invocation
• make status, wait, and result argument help self-describing
• add focused documentation and help-output coverage

Validation

• .venv/bin/python -m pytest -q tests/test_docs.py — 18 passed
• .venv/bin/python -m pytest -q — 130 passed, 24 deselected
• git diff --check