fix: correct link highlighting, update app store validation

GazeTests/Services/AppStoreDetectorTests.swift

@@ -9,9 +9,21 @@
 import Testing
 
 struct AppStoreDetectorTests {
-    
+
     @Test func isAppStoreVersionReturnsFalseInDebug() {
         // In test/debug builds, should always return false
         #expect(AppStoreDetector.isAppStoreVersion == false)
     }
+
+    @Test func isTestFlightReturnsFalseInDebug() {
+        // In test/debug builds, should always return false
+        #expect(AppStoreDetector.isTestFlight == false)
+    }
+
+    @Test func receiptValidationHandlesMissingReceipt() {
+        // When there's no receipt (development build), should return false
+        // This is implicitly tested by isAppStoreVersionReturnsFalseInDebug
+        // but we're documenting the expected behavior
+        #expect(AppStoreDetector.isAppStoreVersion == false)
+    }
 }