* fix(OpenAIClient): handle completions request in reverse proxy, also force prompt by env var * fix(reverseProxyUrl): allow url without /v1/ but add server warning as it will not be compatible with plugins * fix(ModelService): handle reverse proxy without v1 * refactor: make changes cleaner * ci(OpenAIClient): add tests for OPENROUTER_API_KEY, FORCE_PROMPT, and reverseProxyUrl handling in setOptions