TEST: No unitary equivalence tests for scheduling and fusion

[Manideep3969]

Issue

No test verifies that optimized/scheduled circuits produce the same unitary as the input circuit. After the scheduling and fusion bugs are fixed (#32, #33, #37), we need:

1. Operator(scheduled_circuit) == Operator(original_circuit) for all scheduling methods
2. Operator(fused_circuit) ≈ Operator(original_circuit) for fusion (up to global phase)
3. Tests for ALAP producing a DIFFERENT schedule than ASAP
4. Tests for _partition_qubits producing correct groups after cutting

These are critical correctness properties that are currently untested.