Update minimum go version to 1.26.1, golangci-lint to 2.11.2, fix test style (#36876)

Hey, I bumped Go to 1.26.1 and fixed a couple of things I ran into while
poking around.

### Changes

- Bump go.mod from 1.26.0 to 1.26.1 (security patch)
- Bump golangci-lint from v2.10.1 to v2.11.2
- Run make tidy, fmt, lint-go

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude (Opus 4.6) <noreply@anthropic.com>

tests/integration/api_packages_generic_test.go

@@ -140,11 +140,12 @@ func TestPackageGeneric(t *testing.T) {
 		t.Run("ServeDirect", func(t *testing.T) {
 			defer tests.PrintCurrentTest(t)()
 
-			if setting.Packages.Storage.Type == setting.MinioStorageType {
+			switch setting.Packages.Storage.Type {
+			case setting.MinioStorageType:
 				defer test.MockVariableValue(&setting.Packages.Storage.MinioConfig.ServeDirect, true)()
-			} else if setting.Packages.Storage.Type == setting.AzureBlobStorageType {
+			case setting.AzureBlobStorageType:
 				defer test.MockVariableValue(&setting.Packages.Storage.AzureBlobConfig.ServeDirect, true)()
-			} else {
+			default:
 				t.Skip("Test skipped for non-Minio-storage and non-AzureBlob-storage.")
 			}