Attach net/hammock to interior walls
As noted by others, you've got a startling amount of force applied to something that was never designed to hold that force.

If this was my house, I'd build a 4 sided frame of 1.5" square section steel pipe, set in the top corner of the wall and lag bolted securely in a few places per wall to the top plate. I'd also be sure that the corners were solidly bolted together. Use eye bolts to connect to the hammock. You could make most of it disappear by adding crown molding.

What this means is that you're relying on the steel to resist the inward pull of the hammock, and allowing the wall to carry a purely downward load. 

If all that wasn't feasible, get an engineer to run the numbers.