Stabilize feature preview.

src/main.go

@@ -45,12 +45,12 @@ func configureFeatures(ctx context.Context) (err error) {
 	for _, feature := range config.Features {
 		switch feature {
 		// Work-in-progress features:
-		case "preview":
+		// (none)
 		// Permanently unstable features:
 		case "codeberg-pages-compat", "relaxed-idna":
 		// Stabilized features:
 		case "archive-site", "audit", "compress", "patch", "serve-h2c", "existence-cache",
-			"absolute-headers", "expiration":
+			"absolute-headers", "expiration", "preview":
 			logc.Printf(ctx, "feature %s has been stabilized", feature)
 		// Removed or renamed features:
 		case "h2c", "sentry-telemetry-buffer", "site-existence-cache", "domain-existence-cache":

src/wildcard.go

@@ -112,9 +112,6 @@ func TranslateWildcards(wildcardConfigs []WildcardConfig) ([]*WildcardPattern, e
 			}
 		}
 
-		if !config.Feature("preview") {
-			wildcardConfig.PreviewDomain = ""
-		}
 		if wildcardConfig.PreviewDomain != "" {
 			if wildcardConfig.Authorization != "forgejo" {
 				return nil, fmt.Errorf(