Contract Line Defer Successor

This is a small bridge module that connects two contract features: deferring a contract line and managing its successor line. It installs automatically when both features are present.

What changes for users:

• On a contract line that has been deferred, the options to plan a successor, stop the successor plan, stop the line, cancel it or un-cancel it become unavailable. The line is effectively frozen until it is no longer deferred.
• In the contract lines list, deferred lines are shown in a muted (greyed-out) style, while lines that are not deferred keep the normal informational styling. This makes postponed lines easy to spot at a glance.

The module works on the contract line model (contract.line) and adjusts the existing contract line list view from the successor feature. It does not add new menus, fields, reports, emails or scheduled jobs; it only adds these restrictions and the visual highlight.