feat(fase-5.11): selection mode + bulk actions (delete / move / mark-checked)

Long-press on mobile or the new header toggle on desktop puts
/lists/[id] into multi-select mode. Rows render a checkbox on the left,
the stepper + drag handle go away, and swipes + double-tap are disabled.

Chrome during selection mode
  Mobile: header turns into a dark slate-900 action bar with "N selected"
    + Cancel on the left, and a bottom action bar (Delete / Move / Check)
    appears above the BottomTabBar. The sticky add-item form is hidden.
  Desktop: same dark header with Cancel + inline action icons on the right.

Bulk actions
  Delete — one scheduleUndoable with a batch restore (re-inserts all
    snapshots) / batch commit (bulkDeleteItems). Single undo toast.
  Move — opens a bottom sheet / dialog with the collective's other active
    lists + a "Create new list" row that creates an empty list and moves
    into it in a single gesture.
  Mark checked — flips only the selected unchecked items
    (bulkCheckItems with is_checked=false filter), no toggle.

Store helpers (apps/web/src/lib/stores/lists.ts)
  bulkDeleteItems(ids)           → DELETE .in('id', ids)
  bulkMoveItems(ids, newListId)  → UPDATE list_id .in('id', ids)
  bulkCheckItems(ids, userId)    → UPDATE is_checked=true where !is_checked

Entry / exit
  Long-press 500 ms on a row enters with that row pre-selected. Movement
    cancels the long-press intent so it never fights the swipe.
  Single-tap toggles selection while active (instead of invoking the
    no-op short-tap / dbltap-overlay path).
  Cancel button exits + clears selection.

Tests
  apps/web/tests/e2e/selection.test.ts (3 desktop tests)
    SEL-01 toggle enters, row click toggles, Cancel exits
    SEL-02 bulk delete → row gone + undo toast visible
    SEL-03 mark checked → row gains strikethrough
  Mobile long-press tests deferred until WebKit install lands (same
  reason as the swipe-toggle M-series).

i18n additions
  list_select, list_cancel_selection, list_selection_count({n}),
  list_bulk_delete/move/mark_checked, list_undo_bulk_delete({n}),
  list_move_title, list_move_create_new (en/es).

Verification
  just test-e2e → 43 passed + 2 skipped (was 40 + 2).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/tests/e2e/selection.test.ts

@@ -0,0 +1,95 @@
+/**
+ * SEL-series (desktop selection mode) — Fase 5.11
+ *
+ * The long-press entry is gestural and Chromium touch emulation is too flaky
+ * to drive reliably, so mobile-only tests stay deferred. The desktop toggle
+ * button exercises the same state machine end-to-end, so these three tests
+ * give us confidence on the full selection → bulk-action flow.
+ */
+import { test, expect } from '@playwright/test';
+import { USERS } from '../fixtures/users.js';
+import { loginAs } from '../fixtures/login.js';
+
+const SEED_LIST = '/lists/bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb';
+const ADD_ITEM = /add item|añadir producto/i;
+
+test.describe('Selection mode — desktop', () => {
+	test.beforeEach(async ({ page }) => {
+		await loginAs(page, USERS.borja);
+	});
+
+	test('SEL-01: toggle enters selection, row click toggles selection, Cancel exits', async ({
+		page
+	}) => {
+		await page.goto(SEED_LIST);
+		// Seed data guarantees at least one row (Milk, Bread, Eggs…).
+		await expect(page.getByTestId('item-row').first()).toBeVisible({ timeout: 10_000 });
+
+		// Enter selection mode via the header toggle.
+		await page.getByTestId('selection-toggle').click();
+		await expect(page.getByTestId('selection-bar')).toBeVisible({ timeout: 3_000 });
+
+		// Click a row — it becomes selected (data-selected="true").
+		const firstRow = page.getByTestId('item-row').first();
+		await firstRow.click();
+		await expect(firstRow).toHaveAttribute('data-selected', 'true');
+
+		// Selection count label updates.
+		await expect(page.getByTestId('selection-bar')).toContainText(/1 selected|1 seleccionad/i);
+
+		// Cancel exits and clears selection.
+		await page.getByTestId('selection-bar').getByRole('button', { name: /^cancel$|^cancelar$/i }).click();
+		await expect(page.getByTestId('selection-bar')).not.toBeVisible();
+		await expect(firstRow).not.toHaveAttribute('data-selected', 'true');
+	});
+
+	test('SEL-02: bulk delete removes selected rows with an Undo toast', async ({ page }) => {
+		await page.goto(SEED_LIST);
+		// Seed a fresh row we can safely delete.
+		const input = page.getByPlaceholder(ADD_ITEM);
+		await expect(input).toBeVisible({ timeout: 10_000 });
+		const name = `SEL-02-${Date.now()}`;
+		await input.fill(name);
+		await input.press('Enter');
+		const row = page.getByTestId('item-row').filter({ hasText: name }).first();
+		await expect(row).toBeVisible({ timeout: 5_000 });
+
+		// Enter selection, select only our seeded row, then delete.
+		await page.getByTestId('selection-toggle').click();
+		await row.click();
+		await expect(row).toHaveAttribute('data-selected', 'true');
+		await page
+			.getByTestId('selection-bar')
+			.getByRole('button', { name: /^delete$|^eliminar$/i })
+			.click();
+
+		// Row vanishes from the list; undo toast confirms the batch label.
+		await expect(
+			page.getByTestId('item-row').filter({ hasText: name })
+		).toHaveCount(0, { timeout: 5_000 });
+		await expect(page.getByTestId('undo-toast')).toBeVisible({ timeout: 3_000 });
+	});
+
+	test('SEL-03: mark-checked flips all selected unchecked items to checked', async ({ page }) => {
+		await page.goto(SEED_LIST);
+		const input = page.getByPlaceholder(ADD_ITEM);
+		await expect(input).toBeVisible({ timeout: 10_000 });
+		const name = `SEL-03-${Date.now()}`;
+		await input.fill(name);
+		await input.press('Enter');
+		const row = page.getByTestId('item-row').filter({ hasText: name }).first();
+		await expect(row).toBeVisible({ timeout: 5_000 });
+
+		await page.getByTestId('selection-toggle').click();
+		await row.click();
+		await page
+			.getByTestId('selection-bar')
+			.getByRole('button', { name: /mark checked|marcar/i })
+			.click();
+
+		// After bulk check the row should render with strikethrough (muted text).
+		await expect(
+			page.getByTestId('item-row').filter({ hasText: name }).locator('.line-through')
+		).toBeVisible({ timeout: 5_000 });
+	});
+});