Update analytics-evaluations lab: duration to 30 min, rewrite evaluations UCs

Rewrites UC2 and UC3 to follow the evaluations demo script with four
test set creation methods (auto-generate, CSV import, test canvas capture,
manual entry) and structured results review. Reduces lab duration from
45 to 30 minutes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Dewain27

lab-config.yml

@@ -122,7 +122,7 @@ labs:
   core-concepts-analytics-evaluations:
     title: "Monitor Performance and Evaluate Agent Quality"
     difficulty: "Intermediate"
-    duration: 45
+    duration: 30
     section: core
     order: 180
     journeys: [quick-start, business-user, developer]