v1.5.0

Features

• add SphereBoxed to the problems corpus (2b966a5)
• add MA-SW-Chains via SolisWets chain operator (41c59e7)
• add Solis-Wets adaptive random search (28c02c7)
• solver: add matrix-free HessianProduct mode for TrustRegion (a02048e)
• observer: add serde-gated CheckpointWriter observer (ba2d212)
• observer: add Report and History starter observers (aba5ae5)
• observer: add ObserverMode::NewBest (6cc840d)

Bug Fixes

• enforce nam_pool <= pop_size in both builders (69afad8)
• reject non-finite fresh-chain scales (984a572)
• sort NaN costs last in population sorts (a9f7f66)
• repair LS chain eligibility and retention (4852675)