feat: Invoice Editor improvements and code cleanup

Major Invoice Editor updates:
- ✅ Fixed tripled scrollbar issue by removing unnecessary overflow classes
- ✅ Implemented dynamic currency system with JSON data loading
- ✅ Fixed F4 PDF generation error with proper paper size handling
- ✅ Added proper padding to Total section matching table headers
- ✅ Removed print functionality (users can print from PDF download)
- ✅ Streamlined preview toolbar: Back, Size selector, Download PDF
- ✅ Fixed all ESLint warnings and errors
- ✅ Removed console.log statements across codebase for cleaner production
- ✅ Added border-top to Total section for better visual consistency
- ✅ Improved print CSS and removed JSX warnings

Additional improvements:
- Added currencies.json to public folder for proper HTTP access
- Enhanced MinimalTemplate with better spacing and layout
- Clean build with no warnings or errors
- Updated release notes with new features

src/App.js

@@ -13,6 +13,9 @@ import DiffTool from './pages/DiffTool';
 import TextLengthTool from './pages/TextLengthTool';
 import ObjectEditor from './pages/ObjectEditor';
 import TableEditor from './pages/TableEditor';
+import InvoiceEditor from './pages/InvoiceEditor';
+import InvoicePreview from './pages/InvoicePreview';
+import InvoicePreviewMinimal from './pages/InvoicePreviewMinimal';
 import ReleaseNotes from './pages/ReleaseNotes';
 import TermsOfService from './pages/TermsOfService';
 import PrivacyPolicy from './pages/PrivacyPolicy';
@@ -42,6 +45,9 @@ function App() {
             <Route path="/text-length" element={<TextLengthTool />} />
             <Route path="/object-editor" element={<ObjectEditor />} />
             <Route path="/table-editor" element={<TableEditor />} />
+            <Route path="/invoice-editor" element={<InvoiceEditor />} />
+            <Route path="/invoice-preview" element={<InvoicePreview />} />
+            <Route path="/invoice-preview-minimal" element={<InvoicePreviewMinimal />} />
             <Route path="/release-notes" element={<ReleaseNotes />} />
             <Route path="/privacy" element={<PrivacyPolicy />} />
             <Route path="/terms" element={<TermsOfService />} />