Remove support for unused product interfaces (#24965)

We no longer rely on commands and hooks for products, so simplify this code.

server/channels/app/channels.go

@@ -51,9 +51,6 @@ type Channels struct {
 	pluginConfigListenerID        string
 	pluginClusterLeaderListenerID string
 
-	productCommandsLock sync.RWMutex
-	productCommands     []*ProductCommand
-
 	imageProxy *imageproxy.ImageProxy
 
 	// cached counts that are used during notice condition validation
@@ -239,10 +236,6 @@ func NewChannels(services map[product.ServiceKey]any) (*Channels, error) {
 		app: &App{ch: ch},
 	}
 
-	services[product.HooksKey] = &hooksService{
-		ch: ch,
-	}
-
 	services[product.UserKey] = &App{ch: ch}
 
 	services[product.PreferencesKey] = &preferencesServiceWrapper{
@@ -334,28 +327,10 @@ func (ch *Channels) RequestTrialLicense(requesterID string, users int, termsAcce
 		receiveEmailsAccepted)
 }
 
-func (a *App) HooksManager() *product.HooksManager {
-	return a.ch.srv.hooksManager
-}
-
-// Ensure hooksService implements `product.HooksService`
-var _ product.HooksService = (*hooksService)(nil)
-
-type hooksService struct {
-	ch *Channels
-}
-
-func (s *hooksService) RegisterHooks(productID string, hooks any) error {
-	return s.ch.srv.hooksManager.AddProduct(productID, hooks)
-}
-
 func (ch *Channels) RunMultiHook(hookRunnerFunc func(hooks plugin.Hooks) bool, hookId int) {
 	if env := ch.GetPluginsEnvironment(); env != nil {
 		env.RunMultiPluginHook(hookRunnerFunc, hookId)
 	}
-
-	// run hook for the products
-	ch.srv.hooksManager.RunMultiHook(hookRunnerFunc, hookId)
 }
 
 func (ch *Channels) HooksForPluginOrProduct(id string) (plugin.Hooks, error) {
@@ -369,10 +344,5 @@ func (ch *Channels) HooksForPluginOrProduct(id string) (plugin.Hooks, error) {
 		}
 	}
 
-	hooks = ch.srv.hooksManager.HooksForProduct(id)
-	if hooks != nil {
-		return hooks, nil
-	}
-
 	return nil, fmt.Errorf("could not find hooks for id %s", id)
 }