* test(anthropic): cover json_schema envelope edge cases on the Anthropic json tool path
* fix(anthropic): unwrap required-only keys, walk past tool-named envelopes, keep non-ASCII text, flush cut streams, check Vertex output_format
* fix(anthropic): send held json tool text on cut Bedrock Invoke streams and drop a non-object output_format under drop_params
A Bedrock Invoke stream that ends before the json tool block closes now sends the held text and closing brace, as the direct Anthropic stream already did.
A non-object output_format on the Anthropic messages route and its providers is dropped under drop_params and otherwise forwarded, so the provider answers its own 400. Vertex Claude names the proxy setting in its 400 and reads drop_params through the shared helper.
Adds integration cases for the json_schema envelope and the cut stream.
* fix(anthropic): drop a non-object output_format on chat, unwrap a whole envelope on a cut stream, escape lone surrogates
Chat completions to Anthropic, Azure AI, Bedrock Invoke and Vertex now drop a non-object output_format under drop_params, matching /v1/messages. A stream cut after a complete held envelope is unwrapped like a normal end. A json_schema answer holding a lone surrogate keeps its \u escape so the response can still be encoded
* fix(anthropic): join a split answer when the stream ends in its last block
A cut during the second json tool block now runs the held block through
the same flush as a block stop, so it joins the streamed keys or the
earlier split blocks instead of sending two objects back to back. The
Vertex output_format fold drops its unreachable drop_params branch,
since both parent configs drop a non-object value first.
* test(vertex): expect the LiteLLM 400 for a non-object output_format on /v1/messages
