Feature/toasts and error handling (#4496)

# Description of Changes

- Added error handling and toast notifications

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

frontend/src/components/layout/Workbench.tsx

@@ -13,6 +13,7 @@ import PageEditorControls from '../pageEditor/PageEditorControls';
 import Viewer from '../viewer/Viewer';
 import LandingPage from '../shared/LandingPage';
 import Footer from '../shared/Footer';
+import DismissAllErrorsButton from '../shared/DismissAllErrorsButton';
 
 // No props needed - component uses contexts directly
 export default function Workbench() {
@@ -151,6 +152,9 @@ export default function Workbench() {
         selectedToolKey={selectedToolId}
       />
 
+      {/* Dismiss All Errors Button */}
+      <DismissAllErrorsButton />
+
       {/* Main content area */}
       <Box
         className="flex-1 min-h-0 relative z-10 workbench-scrollable "