Implement Event Filtering and Queue Routing

An upstream event pipeline continuously emits events as JSON strings. You need to implement an in-memory routing service that decides which downstream queues should receive each event. Implement an `EventRouter` with the following behavior: - `void subscribe(String queueName, String filterExpression)`: registers a queue with a filter expression. - `List<String> route(String eventJson)`: parses the incoming JSON event, evaluates all registered filters, and returns the names of every queue whose filter matches the event. Return queue names in subscription order. In a real system this method would send to queues, but for this exercise returning queue names is enough. Filter-expression requirements: - A filter compares JSON fields using dot paths, such as `type`, `region`, or `detail.userId`. - Support comparison operators: `==`, `!=`, `>`, `>=`, `<`, `<=`. - Support boolean operators: `AND`, `OR`, `NOT`, and parentheses. - Values may be quoted strings, numbers, booleans, or `null`. - Missing fields should be treated as `null`. - Use JSON type-aware comparison where possible; for example, numeric comparisons should only be applied to numbers. Example: ```text subscribe("usOrders", "type == \"order\" AND region == \"us\"") subscribe("largeOrders", "type == \"order\" AND amount >= 100") subscribe("errors", "detail.level == \"error\" OR type == \"failure\"") route("{\"type\":\"order\",\"region\":\"us\",\"amount\":125}") => ["usOrders", "largeOrders"] ``` You may assume a standard JSON parser/helper is available for converting the event string into a traversable JSON object. Focus on the service structure, filter parsing/evaluation, and routing behavior.