Fix open-folder and create-folder error handling

- Add try/catch to Create Workspace and Open Folder button handlers
  so failures surface an alert instead of silently swallowing errors
- Guard main-process dialog handlers against null/destroyed window
- Guard create-new-file and create-new-folder against missing workspace
- Show user message when New File/New Folder is invoked with no workspace
- Add preload API availability check at renderer startup
- Add 5 smoke tests covering the new guardrails (100 tests total)

Author: brown9804

src/main.js

@@ -163,6 +163,9 @@ function handleWindowClose(event) {
 // ── IPC: folder operations ────────────────────────────────────────────────────
 
 ipcMain.handle('open-folder', async () => {
+  if (!mainWindow || mainWindow.isDestroyed()) {
+    throw new Error('Application window is not ready. Please restart DocFoundry.');
+  }
   const result = await dialog.showOpenDialog(mainWindow, {
     properties: ['openDirectory']
   });
@@ -204,17 +207,24 @@ ipcMain.handle('confirm-save-and-close', async (_event, didSave) => {
 });
 
 ipcMain.handle('create-workspace', async () => {
+  if (!mainWindow || mainWindow.isDestroyed()) {
+    throw new Error('Application window is not ready. Please restart DocFoundry.');
+  }
   const result = await dialog.showOpenDialog(mainWindow, {
     properties: ['openDirectory', 'createDirectory']
   });
   if (result.canceled || result.filePaths.length === 0) return null;
 
   currentFolder = path.resolve(result.filePaths[0]);
   hasUnsavedChanges = false;
-  const entries = fs.readdirSync(currentFolder);
-  if (entries.length === 0) {
-    const readme = path.join(currentFolder, 'README.md');
-    fs.writeFileSync(readme, '# New Workspace\n\nStart writing here.\n', 'utf-8');
+  try {
+    const entries = fs.readdirSync(currentFolder);
+    if (entries.length === 0) {
+      const readme = path.join(currentFolder, 'README.md');
+      fs.writeFileSync(readme, '# New Workspace\n\nStart writing here.\n', 'utf-8');
+    }
+  } catch (err) {
+    console.error('Failed to initialise workspace folder:', err);
   }
   startFileWatcher(currentFolder);
   return readFolderTree(currentFolder);
@@ -223,6 +233,7 @@ ipcMain.handle('create-workspace', async () => {
 // ── IPC: file operations ──────────────────────────────────────────────────────
 
 ipcMain.handle('create-new-file', async (_event, parentDir, fileName) => {
+  if (!currentFolder) throw new Error('No workspace is open. Open or create a workspace first.');
   validateFileName(fileName);
   const resolvedDir = resolveWorkspacePath(currentFolder, parentDir);
   const filePath = path.join(resolvedDir, fileName);
@@ -234,6 +245,7 @@ ipcMain.handle('create-new-file', async (_event, parentDir, fileName) => {
 });
 
 ipcMain.handle('create-new-folder', async (_event, parentDir, folderName) => {
+  if (!currentFolder) throw new Error('No workspace is open. Open or create a workspace first.');
   validateFileName(folderName);
   const resolvedDir = resolveWorkspacePath(currentFolder, parentDir);
   const folderPath = path.join(resolvedDir, folderName);

src/renderer/renderer.js

@@ -92,10 +92,20 @@ if (versionEl && api) {
   versionEl.textContent = `${api.appName} v${api.version}`;
 }
 
+// ── API guard ─────────────────────────────────────────────────────────────────
+if (!api) {
+  window.alert('DocFoundry failed to initialise. Please reinstall the application.');
+}
+
 // ── Button wiring ─────────────────────────────────────────────────────────────
 btnCreate.addEventListener('click', async () => {
-  const tree = await api.createWorkspace();
-  if (tree) showWorkspace(tree);
+  try {
+    const tree = await api.createWorkspace();
+    if (tree) showWorkspace(tree);
+  } catch (err) {
+    console.error('Create workspace failed:', err);
+    window.alert(`Could not create workspace: ${err.message}`);
+  }
 });
 
 btnOpen.addEventListener('click', doOpenFolder);
@@ -414,14 +424,19 @@ function scheduleAutoSave() {
 
 // ── Open folder ───────────────────────────────────────────────────────────────
 async function doOpenFolder() {
-  // Save all dirty tabs before switching
-  for (const tab of tabs) {
-    if (tab.dirty && tab.path) {
-      await saveTab(tab.id);
+  try {
+    // Save all dirty tabs before switching
+    for (const tab of tabs) {
+      if (tab.dirty && tab.path) {
+        await saveTab(tab.id);
+      }
     }
+    const tree = await api.openFolder();
+    if (tree) showWorkspace(tree);
+  } catch (err) {
+    console.error('Open folder failed:', err);
+    window.alert(`Could not open folder: ${err.message}`);
   }
-  const tree = await api.openFolder();
-  if (tree) showWorkspace(tree);
 }
 
 // ── Show workspace ────────────────────────────────────────────────────────────
@@ -666,7 +681,10 @@ function showContextMenu(event, entry) {
 // ── File CRUD ─────────────────────────────────────────────────────────────────
 async function promptNewFile(parentDir) {
   const dir = parentDir || workspaceRoot;
-  if (!dir) return;
+  if (!dir) {
+    window.alert('Open a workspace first before creating files.');
+    return;
+  }
   const name = await showInputDialog({
     title: 'Create new file',
     label: 'File name',
@@ -692,7 +710,10 @@ async function promptNewFile(parentDir) {
 
 async function promptNewFolder(parentDir) {
   const dir = parentDir || workspaceRoot;
-  if (!dir) return;
+  if (!dir) {
+    window.alert('Open a workspace first before creating folders.');
+    return;
+  }
   const name = await showInputDialog({
     title: 'Create new folder',
     label: 'Folder name',

tests/smoke.test.mjs

@@ -300,4 +300,33 @@ describe('Feature surface', () => {
     expect(renderer).toContain("../../node_modules/mermaid/dist/mermaid.min.js");
     expect(renderer).not.toContain('cdn.jsdelivr.net');
   });
+
+  it('renderer guards against missing preload API', () => {
+    const renderer = fs.readFileSync(path.resolve('src/renderer/renderer.js'), 'utf-8');
+    expect(renderer).toContain("if (!api)");
+    expect(renderer).toContain("failed to initialise");
+  });
+
+  it('renderer error-handles the create-workspace and open-folder flows', () => {
+    const renderer = fs.readFileSync(path.resolve('src/renderer/renderer.js'), 'utf-8');
+    expect(renderer).toContain("Could not create workspace:");
+    expect(renderer).toContain("Could not open folder:");
+  });
+
+  it('renderer warns when creating files or folders without a workspace', () => {
+    const renderer = fs.readFileSync(path.resolve('src/renderer/renderer.js'), 'utf-8');
+    expect(renderer).toContain('Open a workspace first before creating files.');
+    expect(renderer).toContain('Open a workspace first before creating folders.');
+  });
+
+  it('main process validates mainWindow before showing dialogs', () => {
+    const main = fs.readFileSync(path.resolve('src/main.js'), 'utf-8');
+    expect(main).toContain('mainWindow.isDestroyed()');
+    expect(main).toContain('Application window is not ready');
+  });
+
+  it('main process guards file/folder creation against missing workspace', () => {
+    const main = fs.readFileSync(path.resolve('src/main.js'), 'utf-8');
+    expect(main).toContain("if (!currentFolder) throw new Error('No workspace is open");
+  });
 });