Moved test database teardown into defer blocks and unified the one-decimal formatting in the Website service.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Services/Website/Tests/Library/Cases/Internal/Pages/SellingPagesTests.swift

@@ -18,7 +18,7 @@ struct SellingPagesTests {
         let html = GradingGuidePage().render()
 
         for step in Grading.scale {
-            #expect(html.contains("<strong>\(step.grade.gradeLabel)</strong><span>\(step.code)</span>"))
+            #expect(html.contains("<strong>\(step.grade.oneDecimal)</strong><span>\(step.code)</span>"))
         }
 
         for defect in Grading.Defect.allCases {