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/openairesponsesinputunion1.md

@@ -0,0 +1,41 @@
+# OpenAIResponsesInputUnion1
+
+
+## Supported Types
+
+### `models.OpenAIResponsesInputMessage1`
+
+```python
+value: models.OpenAIResponsesInputMessage1 = /* values here */
+```
+
+### `models.OpenAIResponsesInputMessage2`
+
+```python
+value: models.OpenAIResponsesInputMessage2 = /* values here */
+```
+
+### `models.OpenAIResponsesInputFunctionCallOutput`
+
+```python
+value: models.OpenAIResponsesInputFunctionCallOutput = /* values here */
+```
+
+### `models.OpenAIResponsesInputFunctionCall`
+
+```python
+value: models.OpenAIResponsesInputFunctionCall = /* values here */
+```
+
+### `models.OutputItemImageGenerationCall`
+
+```python
+value: models.OutputItemImageGenerationCall = /* values here */
+```
+
+### `models.OutputMessage`
+
+```python
+value: models.OutputMessage = /* values here */
+```
+