fix: enable kubedog tracking with atomic/rollback-on-failure helm flags

When using atomic: true with trackMode: kubedog, the --atomic flag was
passed to Helm which caused Helm to wait for resources and rollback
internally before helmfile could start kubedog tracking. This prevented
users from seeing deployment logs and errors.

Changes:
- Add RollbackRelease method to helmexec interface and implementation
- Add appendAtomicFlags function that skips --atomic when kubedog is enabled
- Add handleKubedogFailure function to manually rollback on tracking failure
- Update flagsForUpgrade to use new atomic flag handling
- Add tests for appendAtomicFlags behavior

Now when atomic: true and trackMode: kubedog are both enabled:
1. Helm upgrade runs without --atomic (no internal wait)
2. kubedog tracks resources immediately (users can see logs)
3. If kubedog tracking fails, helmfile manually executes rollback
4. Atomic semantics are preserved

Fixes: #2448
Signed-off-by: yxxhero <aiopsclub@163.com>

pkg/helmexec/exec.go

@@ -837,6 +837,15 @@ func (helm *execer) DeleteRelease(context HelmContext, name string, flags ...str
 	return err
 }
 
+func (helm *execer) RollbackRelease(context HelmContext, name string, flags ...string) error {
+	helm.logger.Infof("Rolling back %v", name)
+	preArgs := make([]string, 0)
+	env := make(map[string]string)
+	out, err := helm.exec(append(append(preArgs, "rollback", name), flags...), env, nil)
+	helm.info(out)
+	return err
+}
+
 func (helm *execer) TestRelease(context HelmContext, name string, flags ...string) error {
 	helm.logger.Infof("Testing %v", name)
 	preArgs := make([]string, 0)

pkg/helmexec/helmexec.go

@@ -31,6 +31,7 @@ type Interface interface {
 	Unittest(name, chart string, flags ...string) error
 	ReleaseStatus(context HelmContext, name string, flags ...string) error
 	DeleteRelease(context HelmContext, name string, flags ...string) error
+	RollbackRelease(context HelmContext, name string, flags ...string) error
 	TestRelease(context HelmContext, name string, flags ...string) error
 	List(context HelmContext, filter string, flags ...string) (string, error)
 	DecryptSecret(context HelmContext, name string, flags ...string) (string, error)