//! Internal hub tooling: memory arena, benchmarking, configuration,
//! determinism, logging, metrics, profiling, utilities, validation, and visualization.
/// Bump-allocator arena for temporary allocations (slices, matrices, scratch pools).
/// Benchmarking harness: timed experiment execution with CSV output.
/// Runtime configuration (iterations, precision, output paths).
/// Deterministic computation: reproducible RNG, Kahan summation, fingerprinting.
/// Structured logging with configurable severity levels.
/// Metrics collection: counters, timers, histograms.
/// Profiling: per-experiment and batch timing with statistical reports.
/// General-purpose helpers: linspace, logspace, formatting, approximate equality.
/// Scientific validation pipeline: reference cases, monotonicity checks, NaN safety, blocking thresholds.
/// Chart generation: line, scatter, bar, histogram, heatmap (SVG output).