Add Hypothesis Fuzzing + more typing + small fixes

[cooperlees]

• Move named_tuples to NamedTypes + typed
• Remove all type comments
• Generate some basic hypothesis tests
  • The typing helped this
• Fixes to ptr.py
  • use .get() to access stats defaulting to 0 if not created
  • Add some extra checks for when dirs don't exist and falsey values
  • Seems an exclude pattern of '.' is bad, so exclude it and log so
• Add GitHub Fuzz action to run