* ci: fix the litellm-tests unit job with sysmon coverage, an env allowlist and coverage upload on failure
* test: replace key-dependent proxy, enterprise and mcp unit tests with synthetic values and integration and e2e coverage
* test: drop key reads at the legacy proxy, enterprise and mcp paths and wire the gemini pass-through split
* ci: move caching, proxy-extras, gateway and enterprise tests into tests/unit and run them from litellm-tests under their legacy flags
* ci: move caching, proxy-extras, gateway and enterprise tests into tests/unit and run them from litellm-tests under their legacy flags
* ci: fail the unit shard when circleci tests split errors
* test: drop restating comments from the gemini pass-through split
* ci: exit the unit shard cleanly when circleci tests split assigns it no files
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Co-authored-by: yuneng <yuneng@berri.ai>
