feat: knowledge pipeline (#25360)

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api/core/workflow/graph/edge.py

@@ -0,0 +1,15 @@
+import uuid
+from dataclasses import dataclass, field
+
+from core.workflow.enums import NodeState
+
+
+@dataclass
+class Edge:
+    """Edge connecting two nodes in a workflow graph."""
+
+    id: str = field(default_factory=lambda: str(uuid.uuid4()))
+    tail: str = ""  # tail node id (source)
+    head: str = ""  # head node id (target)
+    source_handle: str = "source"  # source handle for conditional branching
+    state: NodeState = field(default=NodeState.UNKNOWN)  # edge execution state