I have keys but no locks, I have space but no room, You can enter, but not leave. What am I?

Stack me, sell me, put me on a shelf. Use me, ignore me, just don't burn me. Give me dog ears, write on me, or maybe even consider me holy...just please don't ban me.

I wait in jars or boxes tight, a golden round of pure pastry delight. You swore you’d have just one, then stop, but now the sleeve is at the top.

With every encounter, I dwindle and shrink, Transforming from solid to naught in a blink. Though covered in lather, I keep secrets deep. What am I, the guardian of cleanliness you keep?

From cursed seed I swiftly rise, a spiral path to stolen skies. I pierce the clouds with greedy grace, To reach a giant’s hidden place. What am I, whose sudden bloom, led a boy to gold, and wealthy boon?