test(frontend): add e2e for sort persistence across project switches (#2753)

Reproduces the bug from the issue: change sort to Due date (Earliest
first) in a project's list view, sidebar-navigate to another project,
return to the original — sort should still be applied. Verified RED
against the unfixed useTaskList: URL came back as /projects/1/1 with
no ?sort=.

Author: kolaente

frontend/tests/e2e/project/sort-persistence.spec.ts

@@ -0,0 +1,55 @@
+import {type Page} from '@playwright/test'
+import {test, expect} from '../../support/fixtures'
+import {TaskFactory} from '../../factories/task'
+import {createProjects} from './prepareProjects'
+
+async function selectSortInList(page: Page, optionLabel: string) {
+	await page.locator('.filter-container').getByRole('button', {name: 'Sort', exact: true}).click()
+	await page.getByLabel('Sort by').selectOption({label: optionLabel})
+	await page.getByRole('button', {name: 'Apply sort'}).click()
+}
+
+async function navigateViaSidebar(page: Page, projectTitle: string) {
+	await page.locator('.menu-list .list-menu-link', {
+		has: page.locator('.project-menu-title', {hasText: new RegExp(`^${projectTitle}$`)}),
+	}).first().click()
+}
+
+test.describe('Sort persistence across sidebar navigation (#2753)', () => {
+	test('List view: sort persists after navigating to another project and back', async ({authenticatedPage: page}) => {
+		const projects = await createProjects(2)
+		const [projectA, projectB] = projects
+		await TaskFactory.create(3, {
+			id: '{increment}',
+			project_id: projectA.id,
+			title: 'Task {increment}',
+		})
+
+		const listViewA = projectA.views[0].id
+		await page.goto(`/projects/${projectA.id}/${listViewA}`)
+		await expect(page).not.toHaveURL(/sort=/)
+
+		await selectSortInList(page, 'Due date (Earliest first)')
+		await expect(page).toHaveURL(/sort=due_date:asc/)
+
+		await navigateViaSidebar(page, projectB.title)
+		await expect(page).toHaveURL(new RegExp(`/projects/${projectB.id}/`))
+
+		await navigateViaSidebar(page, projectA.title)
+		await expect(page).toHaveURL(new RegExp(`/projects/${projectA.id}/`))
+		await expect(page).toHaveURL(/sort=due_date:asc/)
+	})
+
+	test('List view: explicit URL sort wins over stored sort', async ({authenticatedPage: page}) => {
+		const projects = await createProjects(1)
+		const listView = projects[0].views[0].id
+
+		// Seed the store with one sort by visiting with it set.
+		await page.goto(`/projects/${projects[0].id}/${listView}?sort=due_date:asc`)
+		await expect(page).toHaveURL(/sort=due_date:asc/)
+
+		// Visit a URL that explicitly sets a different sort — that should win.
+		await page.goto(`/projects/${projects[0].id}/${listView}?sort=priority:desc`)
+		await expect(page).toHaveURL(/sort=priority:desc/)
+	})
+})