Add Live Preview support and reorder counter elements

- Move buttons to right side of number (number, -, +, label)
- Add CodeMirror ViewPlugin for Live Preview rendering
- Counter now works in edit mode (Live Preview)
- Create CounterWidget for editor decorations
- Use Decoration.replace to render counters in editor

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

main.ts

@@ -1,4 +1,42 @@
 import { Plugin, MarkdownPostProcessorContext, MarkdownView } from 'obsidian';
+import { Decoration, DecorationSet, EditorView, WidgetType, ViewPlugin, ViewUpdate } from '@codemirror/view';
+import { RangeSetBuilder } from '@codemirror/state';
+
+class CounterWidget extends WidgetType {
+	constructor(private value: number, private label: string, private plugin: CounterPlugin) {
+		super();
+	}
+
+	toDOM(view: EditorView): HTMLElement {
+		return this.plugin.createCounterElement(this.value, this.label, {} as MarkdownPostProcessorContext);
+	}
+}
+
+function buildCounterDecorations(view: EditorView, plugin: CounterPlugin): DecorationSet {
+	const builder = new RangeSetBuilder<Decoration>();
+	const counterRegex = /~\s*\(\s*(\d*)\s*\)\s*(.+)/g;
+
+	for (let { from, to } of view.visibleRanges) {
+		const text = view.state.doc.sliceString(from, to);
+		let match;
+		counterRegex.lastIndex = 0;
+
+		while ((match = counterRegex.exec(text)) !== null) {
+			const startPos = from + match.index;
+			const endPos = startPos + match[0].length;
+			const value = match[1] === '' ? 0 : parseInt(match[1], 10);
+			const label = match[2].trim();
+
+			const widget = Decoration.replace({
+				widget: new CounterWidget(value, label, plugin),
+			});
+
+			builder.add(startPos, endPos, widget);
+		}
+	}
+
+	return builder.finish();
+}
 
 export default class CounterPlugin extends Plugin {
 	async onload() {
@@ -7,6 +45,28 @@ export default class CounterPlugin extends Plugin {
 		this.registerMarkdownPostProcessor((element, context) => {
 			this.processCounters(element, context);
 		});
+
+		const plugin = this;
+		this.registerEditorExtension(
+			ViewPlugin.fromClass(
+				class {
+					decorations: DecorationSet;
+
+					constructor(view: EditorView) {
+						this.decorations = buildCounterDecorations(view, plugin);
+					}
+
+					update(update: ViewUpdate) {
+						if (update.docChanged || update.viewportChanged) {
+							this.decorations = buildCounterDecorations(update.view, plugin);
+						}
+					}
+				},
+				{
+					decorations: (v) => v.decorations,
+				}
+			)
+		);
 	}
 
 	onunload() {
@@ -147,8 +207,8 @@ export default class CounterPlugin extends Plugin {
 			updateSource(currentValue);
 		});
 
-		container.appendChild(minusButton);
 		container.appendChild(counterDisplay);
+		container.appendChild(minusButton);
 		container.appendChild(plusButton);
 		if (label) {
 			container.appendChild(labelSpan);