Single circuit jobs with mid-circuit measurement sent to IonQ as OpenQASM3

[radumarg]

What:

Adds mid-circuit measurement:

qr, mid, result = QuantumRegister(1, "q"), ClassicalRegister(1, "mid"), ClassicalRegister(2, "result")
qc = QuantumCircuit(qr, mid, result)
qc.h(0)
qc.measure(0, mid[0]) # mid-circuit measurement
qc.x(0)
qc.measure(0, result[0]) # qubit reused after measurement
qc.x(0)
qc.measure(0, result[1])

How:

Single circuit jobs with mid-circuit measurement sent to IonQ as OpenQasm3 via ionq.qasm3.v1

• Routing — circuit_requires_qasm3() detects qubit-reuse-after-measure, reset, and control flow; such circuits serialize to ionq.qasm3.v1 via a newly added serializer that complements the existing QIS serializer. Everything else is unchanged (ionq.circuit.v1).
• Single-circuit only; QASM 3 executes on the simulator and MCM-capable QPUs (Tempo) and is rejected elsewhere server-side.