survinger 0.1.0

• Initial release.
• Core functions: surv_design(), surv_optimize_allocation(), surv_lineage_prevalence(), surv_estimate_delay(), surv_nowcast_lineage(), surv_adjusted_prevalence(), surv_detection_probability(), surv_required_sequences().
• Three prevalence estimators: Horvitz-Thompson, Hajek, post-stratified.
• Three allocation objectives: min_mse, max_detection, min_imbalance.
• Reporting delay estimation with right-truncation correction.
• Diagnostic tools: surv_compare_estimates(), surv_design_effect().
• Example dataset: sarscov2_surveillance.