fix: Simultaneous implicit casts and derefs

This code silently produces invalid WGSL.

  it('disallows implicit casts in d.ref', () => {
    const modify = tgpu.fn([d.ptrFn(d.u32)])((numRef) => {
      'use gpu';
      numRef.$ += 1;
    });

    const main = tgpu.fn([])(() => {
      'use gpu';
      const num = d.f32();
      modify(d.ref(num));
    });

    expect(tgpu.resolve([main])).toMatchInlineSnapshot(`
      "fn modify(numRef: ptr<function, u32>) {
        (*numRef) += 1u;
      }

      fn main() {
        const num = 0f;
        modify((&num));
      }"
    `);
  });

Use the shown TypeScript test with d.ptrFn, d.ref, and tgpu.resolve as the entry point, and trace how the simultaneous implicit cast and dereference are emitted. Verify the focused test no longer produces invalid WGSL and that implicit casts in d.ref are disallowed as intended.