replace log.Fatal/os.Exit with error returns (#941)

* Use stdlib encoders
* Reduce some duplication
* Remove global pagination state
* Dedupe JSON detail types
* Bump golangci-lint

Reviewed-on: https://gitea.com/gitea/tea/pulls/941
Co-authored-by: techknowlogick <techknowlogick@gitea.com>
Co-committed-by: techknowlogick <techknowlogick@gitea.com>

cmd/actions/variables/list_test.go

@@ -4,7 +4,13 @@
 package variables
 
 import (
+	stdctx "context"
+	"os"
 	"testing"
+
+	"code.gitea.io/tea/modules/config"
+	"github.com/stretchr/testify/require"
+	"github.com/urfave/cli/v3"
 )
 
 func TestVariablesListFlags(t *testing.T) {
@@ -61,3 +67,32 @@ func TestVariablesListValidation(t *testing.T) {
 		// This is fine - list commands typically ignore extra args
 	}
 }
+
+func TestRunVariablesListRequiresRepoContext(t *testing.T) {
+	oldWd, err := os.Getwd()
+	require.NoError(t, err)
+
+	require.NoError(t, os.Chdir(t.TempDir()))
+	t.Cleanup(func() {
+		require.NoError(t, os.Chdir(oldWd))
+	})
+
+	config.SetConfigForTesting(config.LocalConfig{
+		Logins: []config.Login{{
+			Name:    "test",
+			URL:     "https://gitea.example.com",
+			Token:   "token",
+			User:    "tester",
+			Default: true,
+		}},
+	})
+
+	cmd := &cli.Command{
+		Name:  CmdVariablesList.Name,
+		Flags: CmdVariablesList.Flags,
+	}
+	require.NoError(t, cmd.Set("login", "test"))
+
+	err = RunVariablesList(stdctx.Background(), cmd)
+	require.ErrorContains(t, err, "remote repository required")
+}