Today's AI news: OpenAI releases GPT-5.5 Instant as the new ChatGPT default with improved math and reduced hallucinations. SAP acquires German AI startup Prior Labs for $1.16B. Anthropic launches finance agents with Microsoft 365 integration. Plus Chrome's silent 4GB AI model install, ElevenLabs' star-studded investor reveal, Apple's iOS 27 AI model choice, and more.