Add validation tests for query optimizations

Co-authored-by: muhlemmer <5411563+muhlemmer@users.noreply.github.com>

internal/query/introspection_test.go

@@ -102,3 +102,19 @@ func TestQueries_ActiveIntrospectionClientByID(t *testing.T) {
 		})
 	}
 }
+
+// TestIntrospectionQueryOptimizations validates that the optimized query 
+// has the expected performance characteristics
+func TestIntrospectionQueryOptimizations(t *testing.T) {
+	// Test that UNION ALL is used instead of UNION
+	assert.Contains(t, introspectionClientByIDQuery, "union all", "Expected 'union all' in optimized query")
+	
+	// Test that aliases are used consistently  
+	assert.Contains(t, introspectionClientByIDQuery, "from config c", "Expected consistent alias usage 'config c'")
+	
+	// Test that keys CTE is simplified
+	assert.Contains(t, introspectionClientByIDQuery, "$2::text as client_id", "Expected simplified keys CTE with $2::text casting")
+	
+	// Test that conditional join logic is present
+	assert.Contains(t, introspectionClientByIDQuery, "and $3 = true", "Expected conditional join logic 'and $3 = true'")
+}