feat: implement EditorPage with file explorer and simulator canvas components

frontend/src/components/editor/FileExplorer.tsx

@@ -58,6 +58,23 @@ const IcoNewFile = () => (
   </svg>
 );
 
+const IcoNewWorkspace = () => (
+  <svg
+    width="22"
+    height="22"
+    viewBox="0 0 24 24"
+    fill="none"
+    stroke="currentColor"
+    strokeWidth="2"
+    strokeLinecap="round"
+    strokeLinejoin="round"
+  >
+    <path d="M22 19a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h5l2 3h9a2 2 0 0 1 2 2z" />
+    <line x1="12" y1="11" x2="12" y2="17" />
+    <line x1="9" y1="14" x2="15" y2="14" />
+  </svg>
+);
+
 const IcoSave = () => (
   <svg
     width="22"
@@ -130,9 +147,10 @@ interface ContextMenu {
 
 interface FileExplorerProps {
   onSaveClick: () => void;
+  onNewClick: () => void;
 }
 
-export const FileExplorer: React.FC<FileExplorerProps> = ({ onSaveClick }) => {
+export const FileExplorer: React.FC<FileExplorerProps> = ({ onSaveClick, onNewClick }) => {
   const {
     fileGroups,
     activeFileId,
@@ -254,6 +272,13 @@ export const FileExplorer: React.FC<FileExplorerProps> = ({ onSaveClick }) => {
       <div className="file-explorer-header">
         <span className="file-explorer-title">WORKSPACE</span>
         <div className="file-explorer-header-actions">
+          <button
+            className="file-explorer-new-btn"
+            title="New workspace (clears boards, components, wires and files)"
+            onClick={onNewClick}
+          >
+            <IcoNewWorkspace />
+          </button>
           <button
             className="file-explorer-save-btn"
             title="Save project (Ctrl+S)"

frontend/src/components/simulator/SimulatorCanvas.tsx

@@ -958,8 +958,7 @@ export const SimulatorCanvas = ({ headerSlot }: SimulatorCanvasProps = {}) => {
         if (selectedComponentId) {
           removeComponent(selectedComponentId);
           setSelectedComponentId(null);
-        } else if (activeBoardId && boards.length > 1) {
-          // Only allow deleting boards if more than one exists
+        } else if (activeBoardId) {
           setBoardToRemove(activeBoardId);
         }
       }
@@ -967,7 +966,7 @@ export const SimulatorCanvas = ({ headerSlot }: SimulatorCanvasProps = {}) => {
 
     window.addEventListener('keydown', handleKeyDown);
     return () => window.removeEventListener('keydown', handleKeyDown);
-  }, [selectedComponentId, removeComponent, activeBoardId, boards.length]);
+  }, [selectedComponentId, removeComponent, activeBoardId]);
 
   // Handle component selection from modal
   const handleSelectComponent = (metadata: ComponentMetadata) => {
@@ -2172,15 +2171,13 @@ export const SimulatorCanvas = ({ headerSlot }: SimulatorCanvasProps = {}) => {
                     padding: '7px 14px',
                     background: 'none',
                     border: 'none',
-                    color: boards.length <= 1 ? '#555' : '#e06c75',
-                    cursor: boards.length <= 1 ? 'default' : 'pointer',
+                    color: '#e06c75',
+                    cursor: 'pointer',
                     fontSize: 13,
                     textAlign: 'left',
                   }}
-                  disabled={boards.length <= 1}
-                  title={boards.length <= 1 ? 'Cannot remove the last board' : undefined}
                   onMouseEnter={(e) => {
-                    if (boards.length > 1) e.currentTarget.style.background = '#2a2d2e';
+                    e.currentTarget.style.background = '#2a2d2e';
                   }}
                   onMouseLeave={(e) => {
                     e.currentTarget.style.background = 'none';

frontend/src/pages/EditorPage.tsx

@@ -24,9 +24,10 @@ import { AppHeader } from '../components/layout/AppHeader';
 import { SaveProjectModal } from '../components/layout/SaveProjectModal';
 import { LoginPromptModal } from '../components/layout/LoginPromptModal';
 import { GitHubStarBanner } from '../components/layout/GitHubStarBanner';
-import { useSimulatorStore } from '../store/useSimulatorStore';
+import { useSimulatorStore, DEFAULT_BOARD_POSITION } from '../store/useSimulatorStore';
 import { useOscilloscopeStore } from '../store/useOscilloscopeStore';
 import { useAuthStore } from '../store/useAuthStore';
+import { useProjectStore } from '../store/useProjectStore';
 import type { CompilationLog } from '../utils/compilationLogger';
 import '../App.css';
 
@@ -140,6 +141,27 @@ export const EditorPage: React.FC = () => {
     }
   }, [user]);
 
+  const handleNewClick = useCallback(() => {
+    if (
+      !window.confirm(
+        'Start a new workspace? This clears every board, component, wire and file. This cannot be undone.',
+      )
+    ) {
+      return;
+    }
+    const sim = useSimulatorStore.getState();
+    sim.boards.forEach((b) => sim.stopBoard(b.id));
+    const ids = sim.boards.map((b) => b.id);
+    ids.forEach((id) => sim.removeBoard(id));
+    sim.setComponents([]);
+    sim.setWires([]);
+    useProjectStore.getState().clearCurrentProject();
+    const newId = useSimulatorStore
+      .getState()
+      .addBoard('arduino-uno', DEFAULT_BOARD_POSITION.x, DEFAULT_BOARD_POSITION.y);
+    useSimulatorStore.getState().setActiveBoardId(newId);
+  }, []);
+
   // Track mobile breakpoint
   useEffect(() => {
     const mq = window.matchMedia(`(max-width: ${MOBILE_BREAKPOINT}px)`);
@@ -357,7 +379,7 @@ export const EditorPage: React.FC = () => {
               <div
                 style={{ width: explorerWidth, flexShrink: 0, display: 'flex', overflow: 'hidden' }}
               >
-                <FileExplorer onSaveClick={handleSaveClick} />
+                <FileExplorer onSaveClick={handleSaveClick} onNewClick={handleNewClick} />
               </div>
               {!isMobile && (
                 <div