fix: LMIC base class multi_bit support in build() and compile()

feat: multi-bit labeling (Wu et al. TCHES 2024)

feat: add XLA jit_compile support for LMIC/LMIC-TSBN

feat: disable sigmoid gates by default in LMIC-TSBN (Section 22)

feat: add gradient clipping (clipnorm) to LMIC/LMIC-TSBN — Phase 1 stability fix

feat: add Focal Loss + Cosine Annealing for LMIC v6

feat: LMIC-TSBN model + persistence fixes across restarts

feat: LMIC architecture - Localized Multi-Input CNN for 16-byte key recovery

feat: training speed optimizations — mixed precision, vectorized augmentation, cached eval predictions

v3: Add DTP + Spectral Decoupling, fix GradNorm OOM, fix _fail_job cancel