fix REST OpenAPI redirect to include mount path

PR #579 fixed a path-absolute redirect bug but introduced a new issue:
the redirect target was missing the /rest mount path, producing
https://transit.land/api/v2/openapi.json instead of
https://transit.land/api/v2/rest/openapi.json.

Root cause: chi v5 does not strip r.URL.Path — it only updates
rctx.RoutePath internally. So r.URL.Path in the handler still contains
the full path (/rest/), the same value the pagination code already
relies on when constructing `meta["next"]` links.

Fix: combine cfg.RestPrefix (for the absolute base) with r.URL.Path
(for the mount path) to produce a correct absolute redirect URL.

Author: drewda

server/rest/rest.go

@@ -54,7 +54,10 @@ func NewServer(graphqlHandler http.Handler) (http.Handler, error) {
 	// Redirect root to OpenAPI documentation
 	r.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		cfg := model.ForContext(r.Context())
-		http.Redirect(w, r, cfg.RestPrefix+"/openapi.json", http.StatusMovedPermanently)
+		// chi does not strip r.URL.Path; it contains the full path (e.g. /rest/)
+		// Use it to build the absolute redirect URL, consistent with how pagination links work
+		path := strings.TrimRight(r.URL.Path, "/")
+		http.Redirect(w, r, cfg.RestPrefix+path+"/openapi.json", http.StatusMovedPermanently)
 	})
 
 	// OpenAPI Schema endpoint