Revert "Say that a deploy keeps only an app's volumes when the app has none"

The owner asked for this commit to be reverted in full
(#254 (comment)). It
removes the no-volume-mounts sentence from the app page and the deploy
log, the constant and tests behind it, the README sentence, and its
TODO.md entry. Later TODO.md entries stay. #248
stays closed as rejected.

Model: opus-5-5

internal/service/deploy/deploy.go

@@ -56,12 +56,6 @@ var (
 	ErrNoPreviousImage = errors.New("no previous image available for rollback")
 )
 
-// NoVolumesWarning is shown on the page of an app with no volume mounts and
-// written into each of its deploy logs.
-const NoVolumesWarning = "This app has no volume mounts, so the files it writes " +
-	"are lost whenever a deploy or rollback replaces its container; " +
-	"a restart of the container keeps them."
-
 // logFlushInterval is how often to flush buffered logs to the database.
 const logFlushInterval = time.Second
 
@@ -375,11 +369,6 @@ func (svc *Service) Deploy(
 
 	svc.logWebhookPayload(bgCtx, deployment, webhookEvent)
 
-	volumes, err := app.GetVolumes(bgCtx)
-	if err == nil && len(volumes) == 0 {
-		_ = deployment.AppendLog(bgCtx, NoVolumesWarning)
-	}
-
 	err = svc.updateAppStatusBuilding(bgCtx, app)
 	if err != nil {
 		return err