Function retire_all_live_ssa_cycles 

fn retire_all_live_ssa_cycles(
    session_id: SessionId,
    ssa_state: &SessionSsaState,
    pix_toolbox: &PixToolbox,
)

Release reconstructor state for the SSA cycles of a session that may still be live.

Called from teardown paths so no builder, verifier or liveness entry is stranded. Bounded to the most recent SSA_TEARDOWN_SWEEP_WINDOW indices: the sweep runs inside the moka eviction listener and in close_session, and the index grows with every completed cycle, so an unbounded walk makes teardown cost proportional to how long the session lived.