Can't transform at mark starting paths.

[LumaKernel]

Like /foo/@bar.

toshiaki61 shows us one solution (#146) but I'm sorry we should continue to discuss how resolving such a problem.

Related:

• can't handle query that contains "." #150
• [$api generation] Route /123 and /$123 conflict. Now it's time to re-think what can we use for dir names and how escaping? aspida#724