Adds owned local TCP peers, a Redis process helper and SigV4 helpers to
tests/integration, and integration contracts for Anthropic and Bedrock wire
shapes, Bedrock role configuration, S3 wire, observed routing, Redis
recovery and stream contracts. Consolidates the four commits previously
stacked on litellm_integration_accounting onto its main-merged tip
tests/integration/conftest.py imported the bare `integration` package. Because
tests/__init__.py and tests/integration/__init__.py both exist, pytest's default
prepend import mode puts only the repo root on sys.path, so that name resolved
only under the PYTHONPATH that tests/integration/run.py injects. Every other
invocation died at conftest import with
ModuleNotFoundError: No module named 'integration' and exit 4, including the
command test_oci_integration.py documents in its own docstring.
The imports now use the tests.integration._support path that pytest actually
resolves, matching the 120 other `from tests.` imports in the suite. run.py's
PYTHONPATH still works because it already puts the repo root on the path.
tests/code_coverage_tests/test_integration_suite_imports.py collects every file
under tests/integration with PYTHONPATH scrubbed and asserts a non-zero
collection count, so an unresolvable import fails the code-quality job instead
of only the developers who run these files by hand. CI runs the three
pre-existing files through the allowlist rather than executing them, which is
why nothing caught this.
