Initial commit: OpenRouter Python SDK

Auto-generated Python SDK for OpenRouter API, providing comprehensive client library with:
- Chat completions and streaming support
- Embeddings API
- Model and provider information
- API key management
- Analytics and usage tracking
- OAuth authentication flows
- Full type hints and error handling

docs/models/openairesponsestoolchoiceunion.md

@@ -0,0 +1,35 @@
+# OpenAIResponsesToolChoiceUnion
+
+
+## Supported Types
+
+### `models.OpenAIResponsesToolChoiceAuto`
+
+```python
+value: models.OpenAIResponsesToolChoiceAuto = /* values here */
+```
+
+### `models.OpenAIResponsesToolChoiceNone`
+
+```python
+value: models.OpenAIResponsesToolChoiceNone = /* values here */
+```
+
+### `models.OpenAIResponsesToolChoiceRequired`
+
+```python
+value: models.OpenAIResponsesToolChoiceRequired = /* values here */
+```
+
+### `models.OpenAIResponsesToolChoiceFunction`
+
+```python
+value: models.OpenAIResponsesToolChoiceFunction = /* values here */
+```
+
+### `models.OpenAIResponsesToolChoice`
+
+```python
+value: models.OpenAIResponsesToolChoice = /* values here */
+```
+