feat(inline-edit): add WYSIWYG inline dashboard editing mode

Replace the disconnected board edit page with inline editing directly
on the board view. Toggle with Ctrl+E or the Edit button. Features:

- Edit mode store with changeset accumulation and batch save
- Floating toolbar (save, discard, add section, board settings, exit)
- Widget hover overlays with edit/delete/drag controls
- Type-specific widget config panels for all 14 widget types
- Section inline editing (title, icon picker, delete)
- "+" buttons for adding widgets and sections inline
- Section-level drag-and-drop reordering via svelte-dnd-action
- Batch save API endpoint (single Prisma transaction)
- Board properties side panel with live theme/wallpaper preview
- Modal widget type picker with search filtering
- Icon picker component with visual grid and search
- Confirmation dialog modal for all destructive actions
- HTML format support for Note widget (in addition to markdown/text)
- Full i18n support (en + ru) for all new UI strings
- Legacy edit page banner linking to new inline mode

src/lib/components/widget/NoteWidget.svelte

@@ -4,7 +4,7 @@
 
 	interface NoteConfig {
 		content: string;
-		format: 'markdown' | 'text';
+		format: 'markdown' | 'text' | 'html';
 	}
 
 	interface Props {
@@ -28,6 +28,9 @@
 					.replace(/\n/g, '<br>')
 			);
 		}
+		if (config.format === 'html') {
+			return DOMPurify.sanitize(config.content);
+		}
 		const raw = marked.parse(config.content, { async: false }) as string;
 		return DOMPurify.sanitize(raw);
 	});