describe unique inodes

[samthor]

• move some server code into "safedoc" which provides locking / inode behavior

  • (this will also eventually provide GC)
  • hides a bit of code from server, could be more easily testable

• add nodes that the server controls, that show when sessions(s) are online

  • it's an error/invalid for sessions to modify them
  • the session gets their ID remapped to self (they don't have to care about their ID)

• eventual plan: locks are implemented by reffing this magic session inode ("it's mine")