Refine backlog policy and runtime guards

Move speculative framework items into Ideas and bump rc.14

Guard tgapi API/uploader setup and nil plugin registrations

Add missing observer Event godoc

tgapi/api.go

@@ -98,6 +98,11 @@ type API struct {
 // Always call Close() when done to release resources.
 func NewAPI(opts *APIOpts) *API {
 	l := utils.CreateLogger("API", utils.GetLoggerLevel())
+	if opts == nil {
+		l.Errorln("Set API options")
+		_ = l.Close()
+		return nil
+	}
 
 	client := opts.client
 	if client == nil {

tgapi/uploader_api.go

@@ -71,6 +71,11 @@ type Uploader struct {
 // NewUploader creates a multipart uploader bound to an API client.
 func NewUploader(api *API) *Uploader {
 	logger := utils.CreateLogger("UPLOADER", utils.GetLoggerLevel())
+	if api == nil {
+		logger.Errorln("api is nil")
+		_ = logger.Close()
+		return nil
+	}
 	return &Uploader{api, logger}
 }