fix: lock LLM to Anthropic Sonnet 4.5 and remove model selector UI#2143

yuki332 wants to merge 3 commits intostackblitz-labs:mainstackblitz-labs/bolt.diy:mainfrom

yuki332:update/strict-llm-modelyuki332/bolt.diy.progate-hackathon:update/strict-llm-modelCopy head branch name to clipboard