Created session/mount.go with all 9P FUSE mount logic previously in core.
Changes:
- New session/mount.go with MountPathFor(), WithMount9P(), and mount lifecycle functions
- WithMount9P() returns execute.Option that wires up OnEnvSet, OnPreDispatch, OnClose hooks
- Updated session.go to use WithMount9P() and MountPathFor() instead of execute.WithMount() and execute.MountPath()
- Mount logic encapsulated in mountState struct with proper synchronization
The mount implementation is now fully contained in the 9p module.
Levi Neely