vercel/ai @ai-sdk/google@4.0.0-canary.52 on GitHub

cfca634: fix(google): emit Vertex no-args streaming tool calls and preserve thoughtSignature
Vertex emits a no-args function call as a single chunk shaped { functionCall: { name: 'X' } } with no args, no partialArgs, and no willContinue. The streaming parser had no branch for this shape, so the call was dropped along with any thoughtSignature it carried. For Gemini 3 thinking models this caused the next multi-turn step to 400 with missing thought_signature. The unary (doGenerate) path had the same drop.
Both paths now emit the call as a complete tool call with '{}' input and propagate thoughtSignature provider metadata.
Fixes #14847.