v0.14.1 — verdict-math boundary tests

Test-only hardening — no behavior or API change.

• Locked the assessDelta degenerate-input boundaries that protect a keep/evict verdict from a divide-by-zero NaN: a single comparable task yields a finite point estimate with null standard error (the savings.length >= 2 guard), and no comparable task yields a null delta rather than NaN. An audit confirmed the verdict math is otherwise free of divide-by-zero / NaN paths.
• 275 tests, green on Node 22 and 24.

Full changelog: v0.14.0...v0.14.1