```python
import heapq

class JobQueue:
    def __init__(self):
        self.heap = []
        self.counter = 0

    def add_job(self, job_id: str, job_data: dict, priority: int = 0):
        heapq.heappush(self.heap, (-priority, self.counter, job_id, job_data))
        self.counter += 1

    def get_next_job(self) -> tuple[str, dict] | None:
        if self.heap:
            _, _, job_id, job_data = heapq.heappop(self.heap)
            return job_id, job_data
        return None
```