[recursion] multi-observe support read from hints

[hero78119]

in read proof, we just read hint slice directly

ceno/ceno_recursion/src/zkvm_verifier/binding.rs

Lines 323 to 327 in d79e874

	iter_zip!(builder, proofs).for_each(|idx_vec, builder| {
	let ptr = idx_vec[0];
	let proof = IOPProverMessageVec::read(builder);
	builder.iter_ptr_set(&proofs, ptr, proof);
	});

then in multi-observe part, we read hint and write back to new array.

ceno/ceno_recursion/src/tower_verifier/program.rs

Lines 62 to 70 in d79e874

	let prover_msg = prover_messages
	.evaluations
	.slice(builder, curr_offset, next_offset);
	builder.assign(&curr_offset, next_offset);
	unsafe {
	let prover_msg_felts = exts_to_felts(builder, &prover_msg);
	challenger_multi_observe(builder, challenger, &prover_msg_felts);
	}

[hero78119]

This part cost 200k cycles