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/chatmessagecontentitem.md

@@ -0,0 +1,29 @@
+# ChatMessageContentItem
+
+
+## Supported Types
+
+### `models.ChatMessageContentItemText`
+
+```python
+value: models.ChatMessageContentItemText = /* values here */
+```
+
+### `models.ChatMessageContentItemImage`
+
+```python
+value: models.ChatMessageContentItemImage = /* values here */
+```
+
+### `models.ChatMessageContentItemAudio`
+
+```python
+value: models.ChatMessageContentItemAudio = /* values here */
+```
+
+### `models.ChatMessageContentItemVideo`
+
+```python
+value: models.ChatMessageContentItemVideo = /* values here */
+```
+