implement grpc gateway and addl handler support

pkg/srv/http/opts/http_config.go

@@ -8,8 +8,9 @@ import (
 
 type AppHTTP struct {
 	Ctx            context.Context
-	Funcs          []HTTPFunc
-	Middleware     []http.Handler
+	Funcs          []HTTPFunc     // Handler funcs, will be wrapped with OTEL
+	Middleware     []http.Handler // Middleware (e.g. request logging)
+	Handlers       []HTTPHandler  // Raw Handler/Mux to add, optional prefix stripping
 	HealthChecks   []HealthCheckFunc
 	CustomListener net.Listener
 	HTTPDone       <-chan any
@@ -20,4 +21,10 @@ type HTTPFunc struct {
 	HandlerFunc http.HandlerFunc
 }
 
+type HTTPHandler struct {
+	Prefix      string // path prefix under which to serve this handler/mux
+	StripPrefix bool   // strip path before sending to handler/mux
+	Handler     http.Handler
+}
+
 type HealthCheckFunc func(context.Context) error