Confirm Soft Values after AGC Approach Limit Change from -12 dBFS to -6 dBFS

[Abraxas3d]

Why Do This: Soft values scale with ADC amplitude. At -6 dBFS we expect +/-3,340 × (1026/594) close to +/-5,766. But we need to measure actual value before recalibrating thresholds.

ILA Signal: dbg_rx_data_soft on ila_msk_rx. Measure peak amplitude when Costas loops are locked.

What Do We Expect to See: +/- 4,000–6,000 range at -6 dBFS with current PI gains. This improves SNR.