[DOP-34705] add recursive query for job_dependencies

[TiGrib]

Change Summary

• Add depth query parameter to GET /v1/jobs/dependencies endpoint to control how many layers of dependency edges are returned (defaults to 1)
• Rewrite JobDependencyRepository.get_dependencies to use recursive CTEs (WITH RECURSIVE) for depth-limited upstream/downstream traversal, replacing the previous flat query

Related issue number

[DOP-34705]

Checklist

• Commit message and PR title is comprehensive
• Keep the change as small as possible
• Unit and integration tests for the changes exist
• Tests pass on CI and coverage does not decrease
• Documentation reflects the changes where applicable
• docs/changelog/next_release/<pull request or issue id>.<change type>.rst file added describing change
  (see CONTRIBUTING.rst for details.)
• My PR is ready to review.

[github-actions]

Coverage Report •

File	Stmts	Miss	Branch	BrPart	Cover	Missing
data_rentgen/server/services
job.py	46	1	0	0	97%	74
TOTAL	7887	971	1232	212	87%