feat: add read-only mode to API and UI, disable write actions

internal/app/config_readonly_test.go

@@ -0,0 +1,29 @@
+package app
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPatchConfigReadOnly(t *testing.T) {
+	prevPath := ConfigPath
+	prevReadOnly := ConfigReadOnly
+	t.Cleanup(func() {
+		ConfigPath = prevPath
+		ConfigReadOnly = prevReadOnly
+	})
+
+	dir := t.TempDir()
+	path := filepath.Join(dir, "config.yaml")
+	require.NoError(t, os.WriteFile(path, []byte(""), 0644))
+
+	ConfigPath = path
+	ConfigReadOnly = true
+
+	err := PatchConfig([]string{"streams", "cam"}, "rtsp://example.com")
+	require.Error(t, err)
+	require.EqualError(t, err, "config is read-only")
+}