optional splat routes (#13547)

Co-authored-by: SteelRazor47 <36779933+SteelRazor47@users.noreply.github.com>

packages/admin/admin-vite-plugin/src/routes/helpers.ts

@@ -4,7 +4,11 @@ export function getRoute(file: string): string {
   const importPath = normalizePath(file)
   return importPath
     .replace(/.*\/admin\/(routes)/, "")
-    .replace(/\[([^\]]+)\]/g, ":$1")
+    .replace("[[*]]", "*?")               // optional splat
+    .replace("[*]", "*")                  // splat
+    .replace(/\(([^\[\]\)]+)\)/g, "$1?")  // optional static,  (foo)
+    .replace(/\[\[([^\]]+)\]\]/g, ":$1?") // optional dynamic, [[foo]]
+    .replace(/\[([^\]]+)\]/g, ":$1")      // dynamic,          [foo]
     .replace(
       new RegExp(
         `/page\\.(${VALID_FILE_EXTENSIONS.map((ext) => ext.slice(1)).join(