add static asset serving support with configurable options

flash/src/main/java/dev/relism/extension/FlashContext.java

@@ -173,4 +173,4 @@ public class FlashContext {
         merged.addAll(routeListeners);
         return cachedListeners = List.copyOf(merged);
     }
-}
+}

flash/src/main/java/dev/relism/http/HttpStatus.java

@@ -1,6 +1,12 @@
 package dev.relism.http;
 
+import dev.relism.models.Request;
+import dev.relism.models.Response;
+import dev.relism.routing.GET;
+import dev.relism.routing.Route;
+
 import java.nio.charset.StandardCharsets;
+import java.util.List;
 
 /**
  * Pre-compiled byte representations of standard HTTP status lines.
@@ -97,4 +103,4 @@ public enum HttpStatus {
         }
         return null;
     }
-}
+}