configuration
Structured, ordered snapshot of the solver's configuration — the same fields the toString implementations expose, in a form that downstream consumers can iterate (reporting, machine-readable summary artifacts, "compare two runs" tooling).
Subclasses override by super.configurationProperties + linkedMapOf(...) so the inherited base fields appear first, followed by the subclass's own additions. Insertion order is preserved via LinkedHashMap so consumers can rely on a stable presentation order.
Values are stringified for portability — TOML, CSV, and HTML tables all consume strings cleanly without type-detection concerns. Numeric consumers can re-parse as needed.