feat: Add Projects and Folders UI (SimpleNote v2)

- New Projects view (projects.js): Lists all projects with cards
- New ProjectView (projectView.js): Project dashboard with folder tree
- Updated API client: Projects and Folders CRUD methods
- New modals: NewProjectModal, NewFolderModal, MoveToFolderModal
- Edit/Delete project functionality
- Updated navigation: ProjectList -> ProjectView -> FolderView
- Consistent dark theme styling

Changes:
- public/js/views/projects.js (NEW)
- public/js/views/projectView.js (NEW)
- public/js/api.js (added Projects/Folders API methods)
- public/js/app.js (added navigation routes)
- public/js/components/sidebar.js (added Projects link)
- public/css/style.css (added project/folder styles)

public/js/components/sidebar.js

@@ -58,6 +58,7 @@ export function renderSidebar({ libraries, tags, selectedLibrary, selectedTag, o
         </div>
         <div class="quick-links">
           <a class="quick-link" data-action="home">📋 All Documents</a>
+          <a class="quick-link" href="#" onclick="window.app.navigate('projects'); return false;">📂 Projects</a>
           <a class="quick-link" href="#" onclick="window.showNewDocModal(); return false;">📄 New Document</a>
           <a class="quick-link" href="#" onclick="window.showNewLibraryModal(); return false;">📁 New Library</a>
         </div>