Chain multiple Playwright route() handlers and use route.fallback() so a request not owned by one handler passes to the next matching handler instead of going to the network

Steps

1. Register multiple page.route(pattern, handler) calls, with overlapping or identical patterns, to build a handler chain
2. Inside a handler, call await route.fallback() instead of route.continue() when this handler shouldn't own the request — fallback() invokes the next matching handler rather than sending the request to the network
3. Remember handler execution order: the last-registered route runs first, and each fallback() call steps back toward the first-registered route
4. Optionally pass overrides to route.fallback({ headers, method, url, postData }) to modify the request before passing it on; matching against subsequent handlers always uses the original request URL, not the overridden one
5. Only a handler that wants to resolve the request should call route.continue(), route.fulfill(), or route.abort(); if every handler calls fallback(), the first-registered handler decides the final outcome