Remove conditional oban_repo_configured?() check that would pull
oban_pro from repo.oban.pro when hex config contained credentials.
The root mix.exs already provides oban_pro via vendored path.
Bumps vendored Oban Pro from 1.6.13 to 1.7.0, which transitively bumps
oban core to 2.22.1 (requires migrations v14) and db_connection to 2.10.0.
- mix.exs constraint: ~> 1.6 → ~> 1.7
- vendor/oban_pro/ replaced with v1.7.0 hex package
- migration 20260430142200: Oban core v12 → v14 (must run first)
- migration 20260430142241: Oban Pro 1.7.0 schema additions
Also corrects a pre-existing constraint name in AgentAssignment that was
left stale by the equipment→devices rename migration (20260117190134).
The unique index is named agent_assignments_device_id_index, but the
schema's unique_constraint/3 still pointed at the old equipment_id name,
causing the test suite to surface Ecto.ConstraintError instead of a
changeset error. Required to get the suite green for this upgrade.
