Merge branch 'jk/path-name-safety-2.5' into jk/path-name-safety-2.6

Merge branch 'jk/path-name-safety-2.5' into jk/path-name-safety-2.6

* jk/path-name-safety-2.5:
  list-objects: pass full pathname to callbacks
  list-objects: drop name_path entirely
  list-objects: convert name_path to a strbuf
  show_object_with_name: simplify by using path_name()
  http-push: stop using name_path
  tree-diff: catch integer overflow in combine_diff_path allocation
  add helpers for detecting size_t overflow