Hello, am I looking for a foundation framework/software would let me build very specific web-based service.
One of the key elements there is ability to author (create) a spreadsheet on a desktop, then pubblish it as a web accessible document where certain authorized people can add /modify rows in that same document.

One other feature of that framework would be that it allows to develop open source and proprietary plugins that can be accessible through the spreadsheet while running on the web (to do calculations/do charts)

I was looking at open-office derivatives and calligra to see if any one can serve (or closer to the spirit in the roadmap) for the above.

Any comments/recommendations are much appreciated
(I am C++ developer with some qt knowledge, so do not mind contributing to the foundational technologies to get them in the above direction).