ChatOpenRouter: 'timeout' parameter violates LangChain seconds convention and forwards as milliseconds

### Submission checklist - [x] This is a bug, not a usage question. - [x] I added a clear and descriptive title that summarizes this issue. - [x] I used the GitHub search to find a similar question and didn't find it. - [x] I am sure that this is a bug in LangChain rather than my code. - [x] The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package). - [x] This is not related to the langchain-community package. - [x] I posted a self-contained, minimal, reproducible example. A maintainer can copy it and run it AS IS. ### Package (Required) - [ ] langchain - [ ] langchain-openai - [ ] langchain-anthropic - [ ] langchain-classic - [ ] langchain-core - [ ] langchain-model-profiles - [ ] langchain-tests - [ ] langchain-text-splitters - [ ] langchain-chroma - [ ] langchain-deepseek - [ ] langchain-exa - [ ] langchain-fireworks - [ ] langchain-groq - [ ] langchain-huggingface - [ ] langchain-mistralai - [ ] langchain-nomic - [ ] langchain-ollama - [x] langchain-openrouter - [ ] langchain-perplexity - [ ] langchain-qdrant - [ ] langchain-xai - [ ] Other / not sure / general ### Related Issues / PRs _No response_ ### Reproduction Steps / Example Code (Python) ```python import asyncio, time from langchain_openrouter import ChatOpenRouter async def main(): # Buggy: 120 is interpreted as 120 ms, not 120 s client = ChatOpenRouter(model="google/gemini-3.7-flash", timeout=120.0, max_retries=0) t0 = time.time() try: r = await client.ainvoke("Hello!") print("OK", r.content) except Exception as e: print(f"{type(e).__name__} after {time.time()-t0:.1f}s: {e}") asyncio.run(main()) ``` ### Error Message and Stack Trace (if applicable) ```shell Hangs indefinitely or crashes with ReadTimeout depending on max_retries. ``` ### Description # `ChatOpenRouter.timeout` is silently treated as milliseconds, not seconds ## Summary `ChatOpenRouter` does not honor the standard LangChain `timeout` contract…