test: add missing tests for cluster edges, handles, colors, and none check method

- backend: cluster edge creation with source/target handles, handle persistence through PATCH
- frontend: cluster color in edgeColors, onConnect preserves sourceHandle/targetHandle

backend/tests/test_edges.py

@@ -100,3 +100,40 @@ async def test_create_edge_requires_auth(client: AsyncClient, two_nodes):
     src, tgt = two_nodes
     res = await client.post("/api/v1/edges", json={"source": src, "target": tgt, "type": "ethernet"})
     assert res.status_code == 401
+
+
+async def test_create_cluster_edge_with_handles(client: AsyncClient, headers: dict, two_nodes):
+    src, tgt = two_nodes
+    res = await client.post(
+        "/api/v1/edges",
+        json={
+            "source": src,
+            "target": tgt,
+            "type": "cluster",
+            "source_handle": "cluster-right",
+            "target_handle": "cluster-left",
+        },
+        headers=headers,
+    )
+    assert res.status_code == 201
+    data = res.json()
+    assert data["type"] == "cluster"
+    assert data["source_handle"] == "cluster-right"
+    assert data["target_handle"] == "cluster-left"
+
+
+async def test_source_and_target_handle_persist_through_update(client: AsyncClient, headers: dict, two_nodes):
+    src, tgt = two_nodes
+    edge_id = (
+        await client.post(
+            "/api/v1/edges",
+            json={"source": src, "target": tgt, "type": "cluster", "source_handle": "cluster-right", "target_handle": "cluster-left"},
+            headers=headers,
+        )
+    ).json()["id"]
+    res = await client.patch(f"/api/v1/edges/{edge_id}", json={"label": "corosync"}, headers=headers)
+    assert res.status_code == 200
+    data = res.json()
+    assert data["source_handle"] == "cluster-right"
+    assert data["target_handle"] == "cluster-left"
+    assert data["label"] == "corosync"

frontend/src/stores/__tests__/canvasStore.test.ts

@@ -117,6 +117,14 @@ describe('canvasStore', () => {
     expect(hasUnsavedChanges).toBe(true)
   })
 
+  it('onConnect preserves sourceHandle and targetHandle for cluster edges', () => {
+    useCanvasStore.getState().onConnect({ source: 'n1', target: 'n2', sourceHandle: 'cluster-right', targetHandle: 'cluster-left' })
+    const { edges } = useCanvasStore.getState()
+    expect(edges).toHaveLength(1)
+    expect(edges[0].sourceHandle).toBe('cluster-right')
+    expect(edges[0].targetHandle).toBe('cluster-left')
+  })
+
   it('addNode with parent_id sets parentId and extent', () => {
     useCanvasStore.getState().addNode(makeNode('parent'))
     useCanvasStore.getState().addNode(makeNode('child', { parent_id: 'parent' }))

frontend/src/utils/__tests__/edgeColors.test.ts

@@ -2,7 +2,7 @@ import { describe, it, expect } from 'vitest'
 import { EDGE_DEFAULT_COLORS } from '../edgeColors'
 import type { EdgeType } from '@/types'
 
-const EDGE_TYPES: EdgeType[] = ['ethernet', 'wifi', 'iot', 'vlan', 'virtual']
+const EDGE_TYPES: EdgeType[] = ['ethernet', 'wifi', 'iot', 'vlan', 'virtual', 'cluster']
 
 describe('EDGE_DEFAULT_COLORS', () => {
   it('has an entry for every EdgeType', () => {
@@ -32,4 +32,8 @@ describe('EDGE_DEFAULT_COLORS', () => {
   it('virtual default is muted gray', () => {
     expect(EDGE_DEFAULT_COLORS.virtual).toBe('#8b949e')
   })
+
+  it('cluster default is proxmox orange', () => {
+    expect(EDGE_DEFAULT_COLORS.cluster).toBe('#ff6e00')
+  })
 })