Proposals: Show Custom Meals in Events (Yes by default, requires the Custom Meal Builder module) adds a custom-meals section to proposals so an event can include built-to-order meals. Two extra rows refine it:

• Proposals CMB: Enable Max/Min Quantity - Yes enforces each ingredient's minimum/maximum quantity inside proposal custom meals.
• Proposals CMB: Allow Exclusive Menu - Yes adds a Show Online toggle to each ingredient's edit page so you can keep some ingredients proposal-only and hide them from the public Custom Meal Builder.

All three also appear as toggles on the Catering Settings page.