fix: Phase 5 - Workflow Editor UX Fixes (Round 3)

Frontend Fixes:
- AdminPromptsPage: Edit button navigates to workflow-editor for workflow type prompts
- WorkflowEditorPage: Fixed save navigation (alert before navigate)
- WorkflowEditorPage: selectedNode derived from selectedNodeId (eliminates stale state)
- FallbackConfig: Show node labels instead of IDs in fallback edge dropdown
- WorkflowCanvas: Enable edge deletion with deletable: true
- WorkflowEditorPage: Hide sidebar when config panel is open

Bugs Fixed:
- C1: Save error "Method Not Allowed" after success
- C2: Edit button in admin doesn't open workflow editor
- H1: Prompt selection not displayed when re-editing node
- H2: Fallback edge dropdown shows node_1/node_2 instead of names
- H3: Cannot delete edges
- M1: Sidebar takes space when config panel open

Technical Changes:
- Replaced useState(selectedNode) with useState(selectedNodeId) + derived selectedNode
- Removed sync useEffect (no longer needed with derived state)
- Added nodes prop to FallbackConfig for label lookup
- Swapped alert/navigate order to prevent navigation errors

Testing: Manual testing required (see manual test cases)

frontend/src/components/workflow/WorkflowCanvas.jsx

@@ -41,7 +41,8 @@ export function WorkflowCanvas({
         maxZoom={2}
         defaultEdgeOptions={{
           animated: false,
-          style: { strokeWidth: 2 }
+          style: { strokeWidth: 2 },
+          deletable: true
         }}
       >
         <Background

frontend/src/components/workflow/panels/FallbackConfig.jsx

@@ -4,15 +4,22 @@
  * Props:
  * - node: React Flow Node object
  * - edges: Array of React Flow edges
+ * - nodes: Array of React Flow nodes (for label lookup)
  * - onChange: (nodeId, updates) => void
  */
-export function FallbackConfig({ node, edges, onChange }) {
+export function FallbackConfig({ node, edges, nodes, onChange }) {
   const fallbackStrategy = node.data.fallback_strategy || 'conservative_skip'
   const fallbackEdge = node.data.fallback_edge || null
 
   // Outgoing Edges von diesem Node
   const outgoingEdges = edges.filter(e => e.source === node.id)
 
+  // Helper: Get node label by ID
+  const getNodeLabel = (nodeId) => {
+    const targetNode = nodes.find(n => n.id === nodeId)
+    return targetNode?.data?.label || nodeId
+  }
+
   const handleStrategyChange = (e) => {
     const strategy = e.target.value
     onChange(node.id, { fallback_strategy: strategy })
@@ -53,7 +60,7 @@ export function FallbackConfig({ node, edges, onChange }) {
             <option value="">-- Kante wählen --</option>
             {outgoingEdges.map(e => (
               <option key={e.id} value={e.id}>
-                {e.data?.label || `Edge → ${e.target}`}
+                {e.data?.label || `Edge → ${getNodeLabel(e.target)}`}
               </option>
             ))}
           </select>

frontend/src/pages/AdminPromptsPage.jsx

@@ -530,7 +530,13 @@ export default function AdminPromptsPage() {
                         justifyContent: 'flex-end'
                       }}>
                         <button
-                          onClick={() => setEditingPrompt(prompt)}
+                          onClick={() => {
+                            if (prompt.type === 'workflow') {
+                              navigate(`/workflow-editor/${prompt.id}`)
+                            } else {
+                              setEditingPrompt(prompt)
+                            }
+                          }}
                           style={{
                             background: 'none',
                             border: 'none',

frontend/src/pages/WorkflowEditorPage.jsx

@@ -34,7 +34,8 @@ export default function WorkflowEditorPage() {
   // State
   const [nodes, setNodes, onNodesChange] = useNodesState([])
   const [edges, setEdges, onEdgesChange] = useEdgesState([])
-  const [selectedNode, setSelectedNode] = useState(null)
+  const [selectedNodeId, setSelectedNodeId] = useState(null)
+  const selectedNode = selectedNodeId ? nodes.find(n => n.id === selectedNodeId) : null
   const [currentPrompt, setCurrentPrompt] = useState(null)
   const [workflowName, setWorkflowName] = useState('Neuer Workflow')
   const [workflowDescription, setWorkflowDescription] = useState('')
@@ -73,16 +74,6 @@ export default function WorkflowEditorPage() {
     setValidationWarnings(warnings)
   }, [nodes, edges])
 
-  // Keep selectedNode in sync with nodes array (wichtig für Config Panel!)
-  useEffect(() => {
-    if (selectedNode) {
-      const updatedNode = nodes.find(n => n.id === selectedNode.id)
-      if (updatedNode && updatedNode !== selectedNode) {
-        setSelectedNode(updatedNode)
-      }
-    }
-  }, [nodes])
-
   // ── Handlers ──────────────────────────────────────────────────────────────
 
   const onConnect = useCallback(
@@ -91,7 +82,7 @@ export default function WorkflowEditorPage() {
   )
 
   const onNodeClick = useCallback((event, node) => {
-    setSelectedNode(node)
+    setSelectedNodeId(node.id)
   }, [])
 
   const handleAddNode = (nodeType) => {
@@ -118,7 +109,7 @@ export default function WorkflowEditorPage() {
 
     setNodes((nds) => nds.filter((n) => n.id !== selectedNode.id))
     setEdges((eds) => eds.filter((e) => e.source !== selectedNode.id && e.target !== selectedNode.id))
-    setSelectedNode(null)
+    setSelectedNodeId(null)
   }
 
   const handleSave = async () => {
@@ -157,8 +148,8 @@ export default function WorkflowEditorPage() {
           graph_data
         })
         setCurrentPrompt({ id: result.id, name: workflowName })
-        navigate(`/workflow-editor/${result.id}`)
         alert('Workflow erstellt!')
+        navigate(`/workflow-editor/${result.id}`)
       }
     } catch (e) {
       setError(e.message)
@@ -219,7 +210,7 @@ export default function WorkflowEditorPage() {
       setCurrentPrompt(null)
       setWorkflowName('Neuer Workflow')
       setWorkflowDescription('')
-      setSelectedNode(null)
+      setSelectedNodeId(null)
       navigate('/workflow-editor/new')
     }
   }
@@ -296,7 +287,7 @@ export default function WorkflowEditorPage() {
       {/* Main Content */}
       <div className="workflow-content">
         {/* Sidebar */}
-        <div className="workflow-sidebar">
+        <div className="workflow-sidebar" style={{ display: selectedNode ? 'none' : 'block' }}>
           <div className="sidebar-section">
             <h3>Workflow-Knoten</h3>
             <div className="node-palette">
@@ -357,7 +348,7 @@ export default function WorkflowEditorPage() {
             <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: 16 }}>
               <h2 style={{ margin: 0 }}>Node-Konfiguration</h2>
               <button
-                onClick={() => setSelectedNode(null)}
+                onClick={() => setSelectedNodeId(null)}
                 style={{
                   background: 'none',
                   border: 'none',
@@ -435,7 +426,7 @@ export default function WorkflowEditorPage() {
                 </div>
 
                 <QuestionAugmentationPanel node={selectedNode} onChange={handleNodeUpdate} />
-                <FallbackConfig node={selectedNode} edges={edges} onChange={handleNodeUpdate} />
+                <FallbackConfig node={selectedNode} edges={edges} nodes={nodes} onChange={handleNodeUpdate} />
               </>
             )}
 
@@ -447,7 +438,7 @@ export default function WorkflowEditorPage() {
                   edges={edges}
                   onChange={handleNodeUpdate}
                 />
-                <FallbackConfig node={selectedNode} edges={edges} onChange={handleNodeUpdate} />
+                <FallbackConfig node={selectedNode} edges={edges} nodes={nodes} onChange={handleNodeUpdate} />
               </>
             )}
 
@@ -464,8 +455,7 @@ export default function WorkflowEditorPage() {
           {validationErrors.map((err, i) => (
             <div key={i} className="validation-error" onClick={() => {
               if (err.nodeId) {
-                const node = nodes.find(n => n.id === err.nodeId)
-                if (node) setSelectedNode(node)
+                setSelectedNodeId(err.nodeId)
               }
             }}>
               ❌ {err.message}
@@ -475,8 +465,7 @@ export default function WorkflowEditorPage() {
           {validationWarnings.map((warn, i) => (
             <div key={i} className="validation-warning" onClick={() => {
               if (warn.nodeId) {
-                const node = nodes.find(n => n.id === warn.nodeId)
-                if (node) setSelectedNode(node)
+                setSelectedNodeId(warn.nodeId)
               }
             }}>
               ⚠️ {warn.message}