Rule.Exclude lists path prefixes that should never be proxied by that
rule, even though they fall under its URLPrefix. A request matching an
Exclude prefix is treated as a non-match for that rule: matching
continues against other configured rules, falling back to the
caller-supplied handler if none apply. Lets a catch-all "/" rule proxy
everything except carved-out paths like "/health".
Adds pkg/server/quickproxy: longest-prefix rule matching over
net/http/httputil.ReverseProxy, falling back to a caller-supplied
handler when the upstream is unreachable or returns 404. Any other
upstream response streams through unchanged. All HTTP methods are
proxied, with a configurable global dial/response-header timeout
(quickproxy.WithTimeout, default 10s).
GoCore-side wiring (config field, webserver2/proxy.go, server.go
route ordering) is tracked separately in that repo.
Hein