[docs] adding support for tinfoil (#1958)

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> [!IMPORTANT]
> Add documentation for Tinfoil as a supported provider under
`openai-generic`, including a new page and navigation update.
> 
>   - **Documentation**:
> - Add Tinfoil to the list of supported providers in
`openai-generic.mdx`.
> - Create new documentation page `tinfoil.mdx` for Tinfoil provider,
detailing its usage with `openai-generic`.
>   - **Configuration**:
> - Update `docs.yml` to include Tinfoil in the navigation under LLM
Client Providers.
> 
> <sup>This description was created by </sup>[<img alt="Ellipsis"
src="https://img.shields.io/badge/Ellipsis-blue?color=175173">](https://www.ellipsis.dev?ref=BoundaryML%2Fbaml&utm_source=github&utm_medium=referral)<sup>
for f1f9542. You can
[customize](https://app.ellipsis.dev/BoundaryML/settings/summaries) this
summary. It will automatically update as commits are pushed.</sup>

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Author: hellovai

fern/03-reference/baml/clients/providers/openai-generic.mdx

@@ -31,6 +31,7 @@ A non-exhaustive list of providers you can use with `openai-generic`:
 | LM Studio | [LM Studio](/ref/llm-client-providers/lmstudio) |
 | Ollama | [Ollama](/ref/llm-client-providers/ollama) |
 | OpenRouter | [OpenRouter](/ref/llm-client-providers/openrouter) |
+| Tinfoil | [Tinfoil](/ref/llm-client-providers/tinfoil) |
 | TogetherAI | [TogetherAI](/ref/llm-client-providers/together) |
 | Unify AI | [Unify AI](/ref/llm-client-providers/unify) |
 | vLLM | [vLLM](/ref/llm-client-providers/vllm) |

fern/03-reference/baml/clients/providers/tinfoil.mdx

@@ -0,0 +1,22 @@
+---
+title: Tinfoil
+---
+
+[Tinfoil](https://tinfoil.sh/) is verifiably private AI inference. 
+
+Tinfoil supports the OpenAI client, allowing you
+to use the [`openai-generic`](/docs/snippets/clients/providers/openai) provider
+with an overridden `base_url`.
+
+
+```baml
+client<llm> TinfoilDeepSeek {
+  provider openai-generic
+  retry_policy Exponential
+  options {
+    base_url "https://deepseek-r1-70b-p.model.tinfoil.sh/v1"
+    model "deepseek-r1-70b"
+    api_key env.TINFOIL_API_KEY
+  }
+}
+```

fern/docs.yml

@@ -763,6 +763,9 @@ navigation:
           - page: "OpenRouter (openai-generic)"
             slug: openrouter
             path: 03-reference/baml/clients/providers/openrouter.mdx
+          - page: "Tinfoil (openai-generic)"
+            slug: tinfoil
+            path: 03-reference/baml/clients/providers/tinfoil.mdx
           - page: "TogetherAI (openai-generic)"
             slug: together
             path: 03-reference/baml/clients/providers/together.mdx