feat: add cache routing alignment and usage visibility for 2.5.0

apps/showcase_ui/src/app/utils/run-info.util.ts

@@ -80,6 +80,14 @@ export function contextPercent(
   return Math.min(100, Math.round(pct * 10) / 10);
 }
 
+/** Session-wide token-weighted cache share; cached input is part of total input. */
+export function cachePercent(cachedTokens: number | null | undefined, promptTokens: number | null | undefined): number | null {
+  if (typeof cachedTokens !== 'number' || typeof promptTokens !== 'number' ||
+      !Number.isFinite(cachedTokens) || !Number.isFinite(promptTokens) ||
+      promptTokens <= 0 || cachedTokens < 0 || cachedTokens > promptTokens) return null;
+  return Math.round(cachedTokens / promptTokens * 1000) / 10;
+}
+
 /**
  * Seconds a session has been (or was) running.
  *