v4.3
API: Move OpenAI-compatible API from extensions/openai to modules/api
API: Add thinking block signature field, fix error codes, clean up logging
API: Improve cache clearing in logprobs
Rename "truncation length" to "context length" in logs
API: Add Anthropic-compatible /v1/messages endpoint
API: Fix _start_cloudflared raising after first attempt instead of exhausting retries