weighted lease

for example:

| **leaseKey** | **leaseOwner** | **leaseWeight** | **leaseCounter** |
| --- | --- | --- | --- |
| task 1 | worker 1 | 1 (default) | x |
| task 2 | worker 2 | 3 | x |
| task 3 | worker 1 | 1 (default) | x |
| task 4 | worker 1 | 1 (default) | x |

comments:
- the default weight of a lease(or task) is 1
- we expect the leaser to partition the work according to the total weight of the tasks.

Look at the existing lease implementation in the repository to understand how leases are currently assigned and tracked. The change involves adding a weight field to lease structures and modifying the partitioning logic to consider total weight. Check for any existing tests around lease assignment to see how to validate the new weighted behavior.

Vom Indexierungsmodell aus dem Issue-Text verfasst.