Merge branch 'jk/path-name-safety-2.6' into jk/path-name-safety-2.7

* jk/path-name-safety-2.6: 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