refactor(actions): extract clickOutside to shared module, replace 5 inline copies

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/actions/clickOutside.svelte.spec.ts

@@ -0,0 +1,64 @@
+import { describe, it, expect, afterEach } from 'vitest';
+
+const { clickOutside } = await import('./clickOutside');
+
+describe('clickOutside action', () => {
+	const nodes: HTMLElement[] = [];
+
+	function makeNode(): HTMLElement {
+		const node = document.createElement('div');
+		document.body.appendChild(node);
+		nodes.push(node);
+		return node;
+	}
+
+	afterEach(() => {
+		nodes.forEach((n) => n.remove());
+		nodes.length = 0;
+	});
+
+	it('registers a capture-phase click listener on mount', () => {
+		const node = makeNode();
+		const original = document.addEventListener.bind(document);
+		let registered = false;
+		document.addEventListener = (type: string, _fn: unknown, opts: unknown) => {
+			if (type === 'click' && opts === true) registered = true;
+			original(type as string, _fn as EventListener, opts as boolean);
+		};
+		clickOutside(node);
+		expect(registered).toBe(true);
+		document.addEventListener = original;
+	});
+
+	it('dispatches clickoutside when clicking outside the node', () => {
+		const node = makeNode();
+		const outside = makeNode();
+		let fired = false;
+		node.addEventListener('clickoutside', () => (fired = true));
+		clickOutside(node);
+		outside.click();
+		expect(fired).toBe(true);
+	});
+
+	it('does not dispatch clickoutside when clicking inside the node', () => {
+		const node = makeNode();
+		const child = document.createElement('span');
+		node.appendChild(child);
+		let fired = false;
+		node.addEventListener('clickoutside', () => (fired = true));
+		clickOutside(node);
+		child.click();
+		expect(fired).toBe(false);
+	});
+
+	it('removes the listener on destroy', () => {
+		const node = makeNode();
+		const outside = makeNode();
+		let count = 0;
+		node.addEventListener('clickoutside', () => count++);
+		const { destroy } = clickOutside(node);
+		destroy();
+		outside.click();
+		expect(count).toBe(0);
+	});
+});

frontend/src/lib/actions/clickOutside.ts

@@ -0,0 +1,15 @@
+export function clickOutside(node: HTMLElement): { destroy: () => void } {
+	function handleClick(event: MouseEvent) {
+		if (node && !node.contains(event.target as Node) && !event.defaultPrevented) {
+			node.dispatchEvent(new CustomEvent('clickoutside'));
+		}
+	}
+
+	document.addEventListener('click', handleClick, true);
+
+	return {
+		destroy() {
+			document.removeEventListener('click', handleClick, true);
+		}
+	};
+}