Develop a outlook office add-in to sync contacts

we require from you to implement an outlook add-in (multi platform, e.g. windows, mac, browser) to work well with Outlook 2021 and later

the add-in provides in outlook:
- iterate over selected (marked) contacts
- provide option to export the contacts via right click context menu or ribbon menu
- the exports via are done via REST api from outlook to api

what is required?
- you develop in C# the add-in
- your code can fetch all contact fields and maps it into a contacts DTO class
- the DTO class can be sent via REST api client to a REST api

UI elements:
- button in the ribbon sesion
- context menu for right clicking on mouse
- both provide a settings dialog to define the REST api endpoint

runtime?
- windows 10, 11
- windows server 2019
- macos
- browser outlook (owa)

delivery?
- into our git repository
- clearly structured code in addin parts, ui parts, DTO and rest api client classes
- you show us the working code in your environment
- you install and test it in our clean environment
- we test it also on our clean environment
- deps are defined in nuget
- built with nuget and msbuilt

finally
- after provided tests, we release payments

MS1:
- create a add-in with settings page and all required buttons and menus
- triggering a button, will result into a simple modal dialog popup
- https://learn.microsoft.com/en-us/office/dev/add-ins/quickstarts/outlook-quickstart?tabs=yeomangenerator

MS2:
- implement the rest api client using a public mock api
- client checks if the contact is available already on api server side
- depending on availabbility either the create or update will be implemented

in later milestones we want to have also the sync of api to outlook, so that outlook contacts get updated or created from api.
But in MS1+MS2 we only require the sync from Outlook to API