* fix(params): carry stream_chunk_size through litellm_params instead of provider params
* test(integration): fence stream_chunk_size out of every provider request body
* test(bedrock): type parametrized stream chunk test params
* test(integration): drop the contracts manifest resurrected by the main merge
* test(bedrock): type the stream_chunk_size test helpers
* test(params): finish AGENTS.md typing pass on stream_chunk_size tests
* test(integration): drop the covers marker from the stream_chunk_size wire test
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Co-authored-by: shrey kharbanda <shreshth@berri.ai>
