docs: Mintlify MDX docs + docs.json; bump Speakeasy to 1.787.0 (#382)

docs/operations/source.mdx

@@ -0,0 +1,22 @@
+---
+title: "Source"
+---
+
+Benchmark source to query. Determines the shape of the returned items. When omitted, returns results from all sources.
+
+## Example Usage
+
+```python
+from openrouter.operations import Source
+
+# Open enum: unrecognized values are captured as UnrecognizedStr
+value: Source = "artificial-analysis"
+```
+
+
+## Values
+
+This is an open enum. Unrecognized values will not fail type checks.
+
+- `"artificial-analysis"`
+- `"design-arena"`