Add constructors and Javadoc comments to improve clarity and completeness across server components, including WebSocket and routing classes.

src/main/java/dev/coph/nextusweb/server/websocket/WebSocketRouter.java

@@ -19,6 +19,12 @@ public final class WebSocketRouter {
     /** Root of the routing trie. */
     private final Node root = new Node();
 
+    /**
+     * Creates an empty WebSocket router with no registered handlers.
+     */
+    public WebSocketRouter() {
+    }
+
     /**
      * Registers a handler at the given path, creating any missing trie nodes. Segments wrapped
      * in braces (e.g. {@code /chat/{room}}) are treated as path parameters.