fix(game): no placement auto-zoom in landscape

Landscape fits the whole board, so the coarse-pointer auto-zoom on tile
placement, drag hover-hold and hint only hid the rest of the position.
Gate all three on portrait; manual double-tap/pinch zoom is unchanged.
New e2e lock both sides: landscape placement stays unzoomed, portrait
placement still auto-zooms (touch-emulated, both engines).

ui/e2e/zoom.spec.ts

@@ -53,6 +53,27 @@ test('zoomed board clamps overscroll at the edge', async ({ page }) => {
   expect(ob.y).toBe('none');
 });
 
+// Placement auto-zoom (touch): in portrait, placing a tile magnifies into it. This is the
+// counterpart of landscape.spec.ts's no-auto-zoom guard — together they lock the gate to
+// orientation only. Skips on an engine whose touch emulation does not flip `(pointer: coarse)`.
+test.describe('touch placement', () => {
+  test.use({ hasTouch: true });
+
+  test('placing a tile auto-zooms the board in portrait', async ({ page }) => {
+    await page.goto('/');
+    await page.getByRole('button', { name: /guest/i }).click();
+    await page.getByRole('button', { name: /Ann/ }).click();
+    await expect(page.locator('[data-cell]').first()).toBeVisible();
+    test.skip(
+      !(await page.evaluate(() => matchMedia('(pointer: coarse)').matches)),
+      'touch emulation does not report a coarse pointer in this engine',
+    );
+    await page.locator('.rack .tile').first().click();
+    await page.locator('[data-cell][data-row="9"][data-col="6"]').click();
+    await expect(page.locator('.viewport.zoomed')).toBeVisible();
+  });
+});
+
 // A hint taken while the board is ALREADY zoomed in must still scroll to the played word — the
 // zoom state does not change, so without an explicit recenter the board stays parked where the
 // player was looking (the reported rough edge). The mock hint plays at the centre star (7,7), so