docs: add flows.filter to api-ref.md

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: jorwoods

docs/api-ref.md

@@ -1828,6 +1828,40 @@ flow = server.flows.get_by_id('1a2a3b4b-5c6c-7d8d-9e0e-1f2f3a4a5b6b')
 result = server.flows.schedule_flow_run('schedule-id-here', flow)
 ```
 
+<br>
+<br>
+
+#### flows.filter
+
+```py
+flows.filter(**kwargs)
+```
+
+Returns a list of flows that match the specified filters. Fields and operators are passed as keyword arguments in the form `field_name=value` or `field_name__operator=value`.
+
+**Supported fields and operators**
+
+Field | Operators
+:--- | :---
+`created_at` | `eq`, `gt`, `gte`, `lt`, `lte`
+`name` | `eq`, `in`
+`owner_name` | `eq`
+`project_id` | `eq`
+`project_name` | `eq`, `in`
+`updated` | `eq`, `gt`, `gte`, `lt`, `lte`
+
+**Returns**
+
+Returns a `QuerySet` of `FlowItem` objects.
+
+**Example**
+
+```py
+matching_flows = server.flows.filter(project_name='My Project')
+for flow in matching_flows:
+    print(flow.name)
+```
+
 <br>
 
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