feat(search): omit default sort while searching so results rank by relevance

The web client always sent sort_by/order_by (the view's default sort), so the
backend's userProvidedSort flag was always true and the new BM25 relevance
ranking never engaged from the web app. When a search is active and the user
has not explicitly chosen a sort, omit the sort entirely so the backend ranks
results by relevance. An explicit user sort still suppresses ranking and
non-search browsing is unchanged.

frontend/src/composables/useTaskList.test.ts

@@ -0,0 +1,83 @@
+import {describe, it, expect, beforeEach, vi} from 'vitest'
+import {defineComponent, h, nextTick} from 'vue'
+import {mount, flushPromises} from '@vue/test-utils'
+import {setActivePinia, createPinia} from 'pinia'
+import {createRouter, createMemoryHistory, type Router} from 'vue-router'
+
+const getAll = vi.fn(async () => [])
+vi.mock('@/services/taskCollection', async (importOriginal) => {
+	const actual = await importOriginal<typeof import('@/services/taskCollection')>()
+	return {
+		...actual,
+		default: class {
+			loading = false
+			totalPages = 1
+			getAll = getAll
+		},
+	}
+})
+
+import {useTaskList} from './useTaskList'
+
+// The second positional argument passed to TaskCollectionService.getAll carries
+// the sort_by/order_by the backend uses to decide whether to rank by relevance.
+function lastRequestParams(): Record<string, unknown> {
+	return getAll.mock.calls.at(-1)?.[1] as Record<string, unknown>
+}
+
+async function mountTaskList(query: Record<string, string>): Promise<Router> {
+	const router = createRouter({
+		history: createMemoryHistory(),
+		routes: [{path: '/', name: 'home', component: {render: () => null}}],
+	})
+	await router.push({path: '/', query})
+	await router.isReady()
+
+	const TestComponent = defineComponent({
+		setup() {
+			useTaskList(() => 1, () => 1)
+			return () => h('div')
+		},
+	})
+
+	mount(TestComponent, {global: {plugins: [router]}})
+	await flushPromises()
+	await nextTick()
+	return router
+}
+
+describe('useTaskList sort handling for relevance ranking', () => {
+	beforeEach(() => {
+		setActivePinia(createPinia())
+		getAll.mockClear()
+	})
+
+	it('omits the sort while searching with the default sort so the backend ranks by relevance', async () => {
+		await mountTaskList({s: 'find me'})
+
+		const params = lastRequestParams()
+		expect(params.s).toBe('find me')
+		expect(params.sort_by).toEqual([])
+		expect(params.order_by).toEqual([])
+	})
+
+	it('keeps an explicit user sort while searching so the user sort is respected', async () => {
+		await mountTaskList({s: 'find me', sort: 'title:asc'})
+
+		const params = lastRequestParams()
+		expect(params.s).toBe('find me')
+		expect(params.sort_by).toEqual(['title'])
+		expect(params.order_by).toEqual(['asc'])
+	})
+
+	it('sends the default sort when not searching', async () => {
+		await mountTaskList({})
+
+		const params = lastRequestParams()
+		expect(params.s).toBe('')
+		expect(params.sort_by).not.toHaveLength(0)
+		// id always sorts last so other sort columns take precedence.
+		expect(params.sort_by).toEqual(['id'])
+		expect(params.order_by).toEqual(['desc'])
+	})
+})

frontend/src/composables/useTaskList.ts

@@ -122,6 +122,14 @@ export function useTaskList(
 	const allParams = computed(() => {
 		const loadParams = {...params.value}
 
+		// Relevance ranking only engages when no sort is sent, so omit the default
+		// sort while searching and let an explicit user sort still take precedence.
+		if (loadParams.s && !sortQuery.value) {
+			loadParams.sort_by = []
+			loadParams.order_by = []
+			return loadParams
+		}
+
 		return formatSortOrder(sortBy.value, loadParams)
 	})