refactor: move undo/redo to toolbar, simplify left panel

Reorganized the UI to improve clarity and reduce duplication:
- Reintroduced Toolbar component below document tabs
- Moved undo/redo controls from left panel to toolbar
- Simplified toolbar to show only undo/redo (removed actor/relation controls)
- Removed History section from left panel
- Left panel now focuses on content management (actors, relations, etc.)

The toolbar now provides a consistent, always-visible location for history
controls across the top of the editor, while the left panel is dedicated to
adding and managing graph content.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/App.tsx

@@ -4,6 +4,7 @@ import GraphEditor from "./components/Editor/GraphEditor";
 import LeftPanel from "./components/Panels/LeftPanel";
 import RightPanel from "./components/Panels/RightPanel";
 import DocumentTabs from "./components/Workspace/DocumentTabs";
+import Toolbar from "./components/Toolbar/Toolbar";
 import MenuBar from "./components/Menu/MenuBar";
 import DocumentManager from "./components/Workspace/DocumentManager";
 import KeyboardShortcutsHelp from "./components/Common/KeyboardShortcutsHelp";
@@ -137,6 +138,9 @@ function AppContent() {
       {/* Document Tabs */}
       <DocumentTabs />
 
+      {/* Toolbar */}
+      {activeDocumentId && <Toolbar />}
+
       {/* Main content area with side panels */}
       <main className="flex-1 overflow-hidden flex">
         {/* Left Panel */}

src/components/Panels/LeftPanel.tsx

@@ -2,14 +2,11 @@ import { useCallback } from 'react';
 import { IconButton, Tooltip } from '@mui/material';
 import ChevronLeftIcon from '@mui/icons-material/ChevronLeft';
 import ChevronRightIcon from '@mui/icons-material/ChevronRight';
-import UndoIcon from '@mui/icons-material/Undo';
-import RedoIcon from '@mui/icons-material/Redo';
 import ExpandMoreIcon from '@mui/icons-material/ExpandMore';
 import ExpandLessIcon from '@mui/icons-material/ExpandLess';
 import { usePanelStore } from '../../stores/panelStore';
 import { useGraphWithHistory } from '../../hooks/useGraphWithHistory';
 import { useEditorStore } from '../../stores/editorStore';
-import { useDocumentHistory } from '../../hooks/useDocumentHistory';
 import { createNode } from '../../utils/nodeUtils';
 
 /**
@@ -41,7 +38,6 @@ const LeftPanel = ({ onDeselectAll, onAddNode }: LeftPanelProps) => {
 
   const { nodeTypes, edgeTypes, addNode } = useGraphWithHistory();
   const { selectedRelationType, setSelectedRelationType } = useEditorStore();
-  const { undo, redo, canUndo, canRedo, undoDescription, redoDescription } = useDocumentHistory();
 
   const handleAddNode = useCallback(
     (nodeTypeId: string) => {
@@ -78,17 +74,6 @@ const LeftPanel = ({ onDeselectAll, onAddNode }: LeftPanelProps) => {
             <ChevronRightIcon fontSize="small" />
           </IconButton>
         </Tooltip>
-
-        {/* Icon indicators for quick reference */}
-        <div className="flex-1 flex flex-col items-center space-y-4 pt-4">
-          <Tooltip title={`Undo: ${undoDescription || 'Nothing to undo'}`} placement="right">
-            <span>
-              <IconButton size="small" onClick={undo} disabled={!canUndo}>
-                <UndoIcon fontSize="small" />
-              </IconButton>
-            </span>
-          </Tooltip>
-        </div>
       </div>
     );
   }
@@ -111,58 +96,6 @@ const LeftPanel = ({ onDeselectAll, onAddNode }: LeftPanelProps) => {
 
       {/* Scrollable content */}
       <div className="flex-1 overflow-y-auto overflow-x-hidden">
-        {/* History Section */}
-        <div className="border-b border-gray-200">
-          <button
-            onClick={() => toggleLeftPanelSection('history')}
-            className="w-full px-3 py-2 flex items-center justify-between bg-gray-50 hover:bg-gray-100 transition-colors"
-          >
-            <span className="text-xs font-semibold text-gray-700">History</span>
-            {leftPanelSections.history ? <ExpandLessIcon fontSize="small" /> : <ExpandMoreIcon fontSize="small" />}
-          </button>
-          {leftPanelSections.history && (
-            <div className="px-3 py-3 space-y-2">
-              <div className="flex items-center space-x-1">
-                <Tooltip
-                  title={undoDescription ? `Undo: ${undoDescription}` : 'Undo (Ctrl+Z)'}
-                  arrow
-                >
-                  <span className="flex-1">
-                    <button
-                      onClick={undo}
-                      disabled={!canUndo}
-                      className="w-full flex items-center space-x-2 px-2 py-1.5 text-xs font-medium text-gray-700 bg-gray-50 rounded hover:bg-gray-100 disabled:opacity-40 disabled:cursor-not-allowed transition-colors"
-                    >
-                      <UndoIcon fontSize="small" />
-                      <span>Undo</span>
-                    </button>
-                  </span>
-                </Tooltip>
-                <Tooltip
-                  title={redoDescription ? `Redo: ${redoDescription}` : 'Redo (Ctrl+Y)'}
-                  arrow
-                >
-                  <span className="flex-1">
-                    <button
-                      onClick={redo}
-                      disabled={!canRedo}
-                      className="w-full flex items-center space-x-2 px-2 py-1.5 text-xs font-medium text-gray-700 bg-gray-50 rounded hover:bg-gray-100 disabled:opacity-40 disabled:cursor-not-allowed transition-colors"
-                    >
-                      <RedoIcon fontSize="small" />
-                      <span>Redo</span>
-                    </button>
-                  </span>
-                </Tooltip>
-              </div>
-              {undoDescription && (
-                <p className="text-xs text-gray-500 italic">
-                  Next: {undoDescription}
-                </p>
-              )}
-            </div>
-          )}
-        </div>
-
         {/* Add Actors Section */}
         <div className="border-b border-gray-200">
           <button

src/components/Toolbar/Toolbar.tsx

@@ -1,143 +1,70 @@
-import { useCallback, useEffect } from 'react';
-import { useGraphWithHistory } from '../../hooks/useGraphWithHistory';
-import { useEditorStore } from '../../stores/editorStore';
 import { useDocumentHistory } from '../../hooks/useDocumentHistory';
-import { createNode } from '../../utils/nodeUtils';
 import UndoIcon from '@mui/icons-material/Undo';
 import RedoIcon from '@mui/icons-material/Redo';
 import { Tooltip, IconButton } from '@mui/material';
 
 /**
- * Toolbar - Graph editing tools
+ * Toolbar - Undo/Redo controls
  *
  * Features:
  * - Undo/Redo buttons with keyboard shortcuts
- * - Add Actor buttons (by type)
- * - Relation type selector
- * - Visual node type palette
+ * - Shows operation descriptions
  *
- * Usage: Placed below tabs, provides quick access to graph editing tools
+ * Usage: Placed below tabs, provides quick access to history controls
  */
 const Toolbar = () => {
-  const { nodeTypes, edgeTypes, addNode } = useGraphWithHistory();
-  const { selectedRelationType, setSelectedRelationType } = useEditorStore();
   const { undo, redo, canUndo, canRedo, undoDescription, redoDescription } = useDocumentHistory();
 
-  // Set default relation type on mount or when edge types change
-  useEffect(() => {
-    if (!selectedRelationType && edgeTypes.length > 0) {
-      setSelectedRelationType(edgeTypes[0].id);
-    }
-  }, [edgeTypes, selectedRelationType, setSelectedRelationType]);
-
-  const handleAddNode = useCallback(
-    (nodeTypeId: string) => {
-      // Create node at center of viewport (approximate)
-      const position = {
-        x: Math.random() * 400 + 100,
-        y: Math.random() * 300 + 100,
-      };
-
-      const nodeTypeConfig = nodeTypes.find((nt) => nt.id === nodeTypeId);
-      const newNode = createNode(nodeTypeId, position, nodeTypeConfig);
-      addNode(newNode);
-    },
-    [addNode, nodeTypes]
-  );
-
-  const selectedEdgeTypeConfig = edgeTypes.find(et => et.id === selectedRelationType);
-
   return (
     <div className="bg-white border-b border-gray-200 shadow-sm">
-      <div className="px-4 py-3">
-        <div className="flex items-center space-x-6">
+      <div className="px-4 py-2">
+        <div className="flex items-center space-x-2">
           {/* Undo/Redo */}
-          <div className="flex items-center space-x-1">
-            <Tooltip
-              title={undoDescription ? `Undo: ${undoDescription} (Ctrl+Z)` : 'Undo (Ctrl+Z)'}
-              arrow
-            >
-              <span>
-                <IconButton
-                  onClick={undo}
-                  disabled={!canUndo}
-                  size="small"
-                  sx={{
-                    '&:disabled': {
-                      opacity: 0.4,
-                    }
-                  }}
-                >
-                  <UndoIcon fontSize="small" />
-                </IconButton>
-              </span>
-            </Tooltip>
-            <Tooltip
-              title={redoDescription ? `Redo: ${redoDescription} (Ctrl+Y)` : 'Redo (Ctrl+Y)'}
-              arrow
-            >
-              <span>
-                <IconButton
-                  onClick={redo}
-                  disabled={!canRedo}
-                  size="small"
-                  sx={{
-                    '&:disabled': {
-                      opacity: 0.4,
-                    }
-                  }}
-                >
-                  <RedoIcon fontSize="small" />
-                </IconButton>
-              </span>
-            </Tooltip>
-          </div>
+          <Tooltip
+            title={undoDescription ? `Undo: ${undoDescription} (Ctrl+Z)` : 'Undo (Ctrl+Z)'}
+            arrow
+          >
+            <span>
+              <IconButton
+                onClick={undo}
+                disabled={!canUndo}
+                size="small"
+                sx={{
+                  '&:disabled': {
+                    opacity: 0.4,
+                  }
+                }}
+              >
+                <UndoIcon fontSize="small" />
+              </IconButton>
+            </span>
+          </Tooltip>
+          <Tooltip
+            title={redoDescription ? `Redo: ${redoDescription} (Ctrl+Y)` : 'Redo (Ctrl+Y)'}
+            arrow
+          >
+            <span>
+              <IconButton
+                onClick={redo}
+                disabled={!canRedo}
+                size="small"
+                sx={{
+                  '&:disabled': {
+                    opacity: 0.4,
+                  }
+                }}
+              >
+                <RedoIcon fontSize="small" />
+              </IconButton>
+            </span>
+          </Tooltip>
 
-          {/* Add Actor */}
-          <div className="flex items-center space-x-2 border-l border-gray-300 pl-6">
-            <h2 className="text-sm font-semibold text-gray-700">Add Actor:</h2>
-            <div className="flex space-x-2">
-              {nodeTypes.map((nodeType) => (
-                <button
-                  key={nodeType.id}
-                  onClick={() => handleAddNode(nodeType.id)}
-                  className="px-3 py-2 text-sm font-medium text-white rounded-md hover:opacity-90 transition-opacity focus:outline-none focus:ring-2 focus:ring-offset-2"
-                  style={{ backgroundColor: nodeType.color }}
-                  title={nodeType.description}
-                >
-                  {nodeType.label}
-                </button>
-              ))}
-            </div>
-          </div>
-
-          {/* Relation Type Selector */}
-          <div className="flex items-center space-x-2 border-l border-gray-300 pl-6">
-            <h2 className="text-sm font-semibold text-gray-700">Relation Type:</h2>
-            <select
-              value={selectedRelationType || ''}
-              onChange={(e) => setSelectedRelationType(e.target.value)}
-              className="px-3 py-2 text-sm border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500"
-              style={{
-                borderLeftWidth: '4px',
-                borderLeftColor: selectedEdgeTypeConfig?.color || '#6b7280'
-              }}
-            >
-              {edgeTypes.map((edgeType) => (
-                <option key={edgeType.id} value={edgeType.id}>
-                  {edgeType.label}
-                </option>
-              ))}
-            </select>
-          </div>
-        </div>
-
-        {/* Instructions */}
-        <div className="mt-3 text-xs text-gray-500">
-          <p>
-            Click a button to add an actor. Drag actors to position them. Select a relation type above, then click
-            and drag from a handle to create a relation between actors.
-          </p>
+          {/* Description text */}
+          {undoDescription && (
+            <span className="text-xs text-gray-500 ml-2">
+              Next: {undoDescription}
+            </span>
+          )}
         </div>
       </div>
     </div>