>At its core, capitalism is simply the codification of a win-win transaction between two or more parties. I work for your company, you pay me X salary.
I don't think that's true; I view capitalism as a mode of production, subsisting on private ownership of the social means of production, the primacy of wage labour (this is the aspect you mentioned) but also the production of commodities (i.e exchange is to be maximised rather than the use of products) and lastly that production is for profit and accumulation of capital rather than satisfying social wants.
>Whereas socialism is the codification of a win-lose, non-consensual transaction. You're doing well, give me your money so I can give it to a third party, or else.
This is not what Socialism is about. Socialism is contrasted with capitalism not by money redistribution (in fact, no redistribution of non-social MoP produce or money occurs) but by the fact that means of production would be owned collectively by workers, and used for their benefit. The workers are also the consumers. This two-faceted benefit would seem to be a win-win in my opinion.
>non-consensual transaction.
The non-consensual part of Socialism is seizing the means of production from capitalists (either via revolution or otherwise). The non-consensual part of capitalism is the fact that people must sell their labour-power as a commodity on a market to private property owners in order to survive. Although all parties appear at face value to be participating in a system of equal and fair uncoerced exchanges, a look at the more extreme examples in our world of sweatshop labour or prostitution by necessity gives an opposite picture. These people are free to quit at any time, but have little option otherwise. They certainly can't accumulate sufficient capital to start a self-employment model of business.