feat: Workflow Editor UX improvements - validation and notifications

**Problem 1: Validation footer covers mobile menu**
- Fixed bottom validation panel (z-index 1000) overlapped mobile nav
- Solution: Removed bottom panel, added inline validation in config panel header

**Problem 2: Alert dialogs for save success**
- alert() blocks UI and requires OK click for every save
- Solution: Toast notifications (auto-close after 3s, non-blocking)

**Problem 3: Validation shows only counts, not details**
- Footer showed "1 Error, 2 Warnings" without details
- Solution: Inline display shows all error/warning messages with click-to-navigate

**New Components:**
- Toast.jsx: Auto-closing notifications (success/error/warning/info)
- ConfirmDialog.jsx: Modal confirmation dialogs (for future save-on-close)

**Changes:**
- WorkflowEditorPage: Inline validation in config panel, toast state
- Removed fixed bottom .validation-panel (no mobile overlap)
- Toast for save success instead of alert()

**Still TODO (separate commit):**
- Save confirmation when closing/switching nodes with unsaved changes
- Dirty state tracking

Part 3: Inline Prompts - UX polish (validation + notifications)

frontend/src/components/ConfirmDialog.jsx

@@ -0,0 +1,106 @@
+/**
+ * ConfirmDialog Component
+ *
+ * Modal confirmation dialog
+ *
+ * Props:
+ * - message: string
+ * - onConfirm: callback when confirmed
+ * - onCancel: callback when cancelled
+ * - confirmText: string (default: 'OK')
+ * - cancelText: string (default: 'Abbrechen')
+ * - type: 'warning' | 'danger' | 'info' (default: 'warning')
+ */
+export function ConfirmDialog({
+  message,
+  onConfirm,
+  onCancel,
+  confirmText = 'OK',
+  cancelText = 'Abbrechen',
+  type = 'warning'
+}) {
+  const colors = {
+    warning: '#FFC107',
+    danger: 'var(--danger)',
+    info: 'var(--accent)'
+  }
+
+  return (
+    <div
+      style={{
+        position: 'fixed',
+        top: 0,
+        left: 0,
+        right: 0,
+        bottom: 0,
+        background: 'rgba(0,0,0,0.5)',
+        display: 'flex',
+        alignItems: 'center',
+        justifyContent: 'center',
+        zIndex: 20000
+      }}
+      onClick={onCancel}
+    >
+      <div
+        style={{
+          background: 'var(--surface)',
+          borderRadius: '12px',
+          padding: '24px',
+          maxWidth: '500px',
+          width: '90%',
+          boxShadow: '0 8px 24px rgba(0,0,0,0.3)'
+        }}
+        onClick={(e) => e.stopPropagation()}
+      >
+        <div
+          style={{
+            fontSize: '16px',
+            marginBottom: '24px',
+            color: 'var(--text1)',
+            lineHeight: '1.5'
+          }}
+        >
+          {message}
+        </div>
+
+        <div
+          style={{
+            display: 'flex',
+            gap: '12px',
+            justifyContent: 'flex-end'
+          }}
+        >
+          <button
+            onClick={onCancel}
+            style={{
+              padding: '8px 16px',
+              border: '1px solid var(--border)',
+              borderRadius: '6px',
+              background: 'var(--surface2)',
+              color: 'var(--text1)',
+              cursor: 'pointer',
+              fontSize: '14px'
+            }}
+          >
+            {cancelText}
+          </button>
+          <button
+            onClick={onConfirm}
+            style={{
+              padding: '8px 16px',
+              border: 'none',
+              borderRadius: '6px',
+              background: colors[type],
+              color: type === 'warning' ? '#000' : 'white',
+              cursor: 'pointer',
+              fontSize: '14px',
+              fontWeight: 500
+            }}
+          >
+            {confirmText}
+          </button>
+        </div>
+      </div>
+    </div>
+  )
+}

frontend/src/components/Toast.jsx

@@ -0,0 +1,95 @@
+import { useEffect } from 'react'
+
+/**
+ * Toast Notification Component
+ *
+ * Auto-closing notification that appears at the top of the screen
+ *
+ * Props:
+ * - message: string
+ * - type: 'success' | 'error' | 'warning' | 'info'
+ * - duration: number (ms, default 3000)
+ * - onClose: callback when toast closes
+ */
+export function Toast({ message, type = 'info', duration = 3000, onClose }) {
+  useEffect(() => {
+    const timer = setTimeout(() => {
+      if (onClose) onClose()
+    }, duration)
+
+    return () => clearTimeout(timer)
+  }, [duration, onClose])
+
+  const styles = {
+    success: {
+      background: '#4CAF50',
+      color: 'white',
+      icon: '✅'
+    },
+    error: {
+      background: 'var(--danger)',
+      color: 'white',
+      icon: '❌'
+    },
+    warning: {
+      background: '#FFC107',
+      color: '#856404',
+      icon: '⚠️'
+    },
+    info: {
+      background: 'var(--accent)',
+      color: 'white',
+      icon: 'ℹ️'
+    }
+  }
+
+  const style = styles[type] || styles.info
+
+  return (
+    <div
+      style={{
+        position: 'fixed',
+        top: '80px',
+        left: '50%',
+        transform: 'translateX(-50%)',
+        background: style.background,
+        color: style.color,
+        padding: '12px 24px',
+        borderRadius: '8px',
+        boxShadow: '0 4px 12px rgba(0,0,0,0.3)',
+        zIndex: 10000,
+        display: 'flex',
+        alignItems: 'center',
+        gap: '8px',
+        fontSize: '14px',
+        fontWeight: 500,
+        minWidth: '300px',
+        maxWidth: '600px',
+        animation: 'slideDown 0.3s ease-out'
+      }}
+      onClick={onClose}
+    >
+      <span style={{ fontSize: '18px' }}>{style.icon}</span>
+      <span>{message}</span>
+    </div>
+  )
+}
+
+// Add animation CSS if not already in global styles
+const styleElement = document.createElement('style')
+styleElement.textContent = `
+  @keyframes slideDown {
+    from {
+      opacity: 0;
+      transform: translateX(-50%) translateY(-20px);
+    }
+    to {
+      opacity: 1;
+      transform: translateX(-50%) translateY(0);
+    }
+  }
+`
+if (!document.querySelector('style[data-toast-styles]')) {
+  styleElement.setAttribute('data-toast-styles', 'true')
+  document.head.appendChild(styleElement)
+}

frontend/src/pages/WorkflowEditorPage.jsx

@@ -19,6 +19,8 @@ import { PlaceholderPicker } from '../components/workflow/panels/PlaceholderPick
 import { WorkflowExecutePanel } from '../components/workflow/panels/WorkflowExecutePanel'
 import { WorkflowResultViewer } from '../components/workflow/panels/WorkflowResultViewer'
 import { InlineTemplateEditor } from '../components/workflow/panels/InlineTemplateEditor'
+import { Toast } from '../components/Toast'
+import { ConfirmDialog } from '../components/ConfirmDialog'
 import '../styles/workflowEditor.css'
 
 // Node-Type Mapping
@@ -55,6 +57,10 @@ export default function WorkflowEditorPage() {
   const endNodeTextareaRef = useRef(null)
   const inlineTemplateTextareaRef = useRef(null)
 
+  // Toast & Confirm Dialog
+  const [toast, setToast] = useState(null)
+  const [confirmDialog, setConfirmDialog] = useState(null)
+
   // Load available basis prompts for Analysis nodes
   useEffect(() => {
     async function loadPrompts() {
@@ -155,7 +161,7 @@ export default function WorkflowEditorPage() {
           description: workflowDescription,
           graph_data
         })
-        alert('Workflow gespeichert!')
+        setToast({ message: '✅ Workflow gespeichert!', type: 'success' })
       } else {
         // Create new
         console.log('✨ Creating new workflow')
@@ -167,7 +173,7 @@ export default function WorkflowEditorPage() {
         })
         console.log('✅ Workflow created:', result)
         setCurrentPrompt({ id: result.id, slug: result.slug, name: workflowName })
-        alert('Workflow erstellt!')
+        setToast({ message: '✅ Workflow erstellt!', type: 'success' })
         console.log('🚀 Navigating to:', `/workflow-editor/${result.id}`)
         navigate(`/workflow-editor/${result.id}`)
       }
@@ -462,6 +468,33 @@ export default function WorkflowEditorPage() {
               </button>
             </div>
 
+            {/* Inline Validation Display */}
+            {(validationErrors.length > 0 || validationWarnings.length > 0) && (
+              <div style={{
+                background: validationErrors.length > 0 ? '#ffebee' : '#fff3cd',
+                border: `1px solid ${validationErrors.length > 0 ? 'var(--danger)' : '#FFC107'}`,
+                borderRadius: '8px',
+                padding: '12px',
+                marginBottom: '16px'
+              }}>
+                <div style={{ fontWeight: 600, marginBottom: '8px', color: validationErrors.length > 0 ? 'var(--danger)' : '#856404' }}>
+                  {validationErrors.length > 0 ? `❌ ${validationErrors.length} Fehler` : `⚠️ ${validationWarnings.length} Warnungen`}
+                </div>
+                {validationErrors.map((err, i) => (
+                  <div key={`err-${i}`} style={{ fontSize: '13px', marginBottom: '4px', color: 'var(--danger)', cursor: err.nodeId ? 'pointer' : 'default' }}
+                    onClick={() => err.nodeId && setSelectedNodeId(err.nodeId)}>
+                    • {err.message}
+                  </div>
+                ))}
+                {validationWarnings.map((warn, i) => (
+                  <div key={`warn-${i}`} style={{ fontSize: '13px', marginBottom: '4px', color: '#856404', cursor: warn.nodeId ? 'pointer' : 'default' }}
+                    onClick={() => warn.nodeId && setSelectedNodeId(warn.nodeId)}>
+                    • {warn.message}
+                  </div>
+                ))}
+              </div>
+            )}
+
             {/* Basis-Konfiguration */}
             <div className="config-section">
               <label>Node-Name</label>
@@ -624,36 +657,7 @@ export default function WorkflowEditorPage() {
         )}
       </div>
 
-      {/* Validation Panel */}
+      {/* Validation Panel - REMOVED (moved to config panel header) */}
-      {(validationErrors.length > 0 || validationWarnings.length > 0) && (
-        <div className="validation-panel">
-          {validationErrors.map((err, i) => (
-            <div key={i} className="validation-error" onClick={() => {
-              if (err.nodeId) {
-                setSelectedNodeId(err.nodeId)
-              }
-            }}>
-              ❌ {err.message}
-            </div>
-          ))}
-
-          {validationWarnings.map((warn, i) => (
-            <div key={i} className="validation-warning" onClick={() => {
-              if (warn.nodeId) {
-                setSelectedNodeId(warn.nodeId)
-              }
-            }}>
-              ⚠️ {warn.message}
-            </div>
-          ))}
-
-          {validationErrors.length === 0 && validationWarnings.length > 0 && (
-            <div className="validation-success">
-              ✅ Workflow ist valide ({validationWarnings.length} Warnungen)
-            </div>
-          )}
-        </div>
-      )}
 
       {/* Execution Result Viewer */}
       {executionResult && (
@@ -672,6 +676,28 @@ export default function WorkflowEditorPage() {
           onClose={() => setShowPlaceholderPicker(false)}
         />
       )}
+
+      {/* Toast Notification */}
+      {toast && (
+        <Toast
+          message={toast.message}
+          type={toast.type}
+          duration={toast.duration || 3000}
+          onClose={() => setToast(null)}
+        />
+      )}
+
+      {/* Confirm Dialog */}
+      {confirmDialog && (
+        <ConfirmDialog
+          message={confirmDialog.message}
+          onConfirm={confirmDialog.onConfirm}
+          onCancel={() => setConfirmDialog(null)}
+          confirmText={confirmDialog.confirmText}
+          cancelText={confirmDialog.cancelText}
+          type={confirmDialog.type}
+        />
+      )}
     </div>
   )
 }