Spring AI 2.1.0-M1 fixes 60-second streaming timeout regression

Spring AI 2.1.0-M1, released September 25, 2026, fixes a regression from 2.0.1 where a hard-coded 60-second per-call timeout ignored spring.ai.openai.timeout and killed longer streaming turns. The milestone also adds ordered message parts, OpenAI Responses endpoint support and VectorStore.upsert() for pre-computed embeddings.

• The 2.0.1 regression killed any stream longer than 60 seconds, overriding configured timeouts
• Messages are now an ordered list of typed parts: text, reasoning, tool calls, media
• Setting spring.ai.openai.chat.api=responses enables OpenAI Responses for tool calling with reasoning
• VectorStore.upsert() accepts pre-computed embeddings with stable ids for idempotent ingestion