fix: prevent tool name duplication in streaming accumulator (MiniMax/NVIDIA NIM)

Based on #11984 by @maxchernin.  Fixes #8259.

Some providers (MiniMax M2.7 via NVIDIA NIM) resend the full function
name in every streaming chunk instead of only the first.  The old
accumulator used += which concatenated them into 'read_fileread_file'.

Changed to simple assignment (=), matching the OpenAI Node SDK, LiteLLM,
and Vercel AI SDK patterns.  Function names are atomic identifiers
delivered complete — no provider splits them across chunks, so
concatenation was never correct semantics.

scripts/release.py

@@ -264,6 +264,7 @@ AUTHOR_MAP = {
     "asurla@nvidia.com": "anniesurla",
     "limkuan24@gmail.com": "WideLee",
     "aviralarora002@gmail.com": "AviArora02-commits",
+    "jarvischer@gmail.com": "maxchernin",
 }