Make ToolCallLimitMiddleware proactive via before_model hook

### Checked other resources - [x] This is a feature request, not a bug report or usage question. - [x] I added a clear and descriptive title that summarizes the feature request. - [x] I used the GitHub search to find a similar feature request and didn't find it. - [x] I checked the LangChain documentation and API reference to see if this feature already exists. - [x] This is not related to the langchain-community package. ### Package (Required) - [x] 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 - [ ] langchain-openrouter - [ ] langchain-perplexity - [ ] langchain-qdrant - [ ] langchain-xai - [ ] Other / not sure / general ### Feature Description The `ToolCallLimitMiddleware` is currently reactive, which means the limit logic is invoked after the limit is reached which has few downsides: 1. This might make LLM to utilize tools less effectively since it is not aware of tool limit from the beginning. When the limit is reached we panick the LLM by sending tool call limit reached message all of a sudden which it was not aware of 2. The reactive way of detecting tool call limit leads to additional tool call which doesn't get used. ### Use Case LLM can plan ahead if it is aware of the concept of tool call limit and MAYBE converge better. Compare it with how a human would act in real life, in a game if we are aware of no of retries/no of tries left we do plan accordingly right? ### Proposed Solution This can be implemted by using `@before_model` hook where an additional message is passed which informs LLM how many tool calls left. ```py [ HumanMessage(content='Get all current affairs across the globe'), HumanMessage(conten…