Leaf broth, Hot or cold, Spill me? Secrets unfold

I'm light and airy, yet I hold my shape, A cushion for comfort, or a wave's playful escape, In a cup of coffee, I'm a tasty delight, In a mattress, I'm the key to a peaceful night.

In the playground of balance, a wooden plank dances, as laughter lifts and falls, a cycle of ups and downs in rhythmic harmony.

I am a golden mountain, yet I have no rock, Born of the harvest, I am built for the stock. If you lose a tiny needle, you must search through me, But if you light a match, I turn to ashes instantly. What am I?

I hang on a neck but I’m not a tie, With every step, I testify. Clang and clatter through field and dell, A farmyard’s chime you know too well.