Fix generate_sub_moved_events corrupting paths with unbounded str.replace

[bysiber]

generate_sub_moved_events uses str.replace() to convert destination paths back to source paths when generating subevents for directory moves. Since str.replace() without a count argument replaces all occurrences of the substring, this corrupts paths when the directory name being moved also appears elsewhere in the subtree.

Example:

Moving /tmp/bar/ (containing data/bar/file.txt) to /tmp/foo/:

full_path = "/tmp/foo/data/bar/file.txt"
dest_dir_path = "/tmp/foo"
src_dir_path = "/tmp/bar"

# Before (WRONG) — replaces both occurrences of "foo":
full_path.replace(dest_dir_path, src_dir_path)
# → depending on overlap, can mangle the interior path components

# This is especially visible with short or common directory names.

Fix: replace only the leading prefix using string slicing instead of str.replace():

renamed_path = src_dir_path + full_path[len(dest_dir_path):] if src_dir_path else ""

This ensures only the prefix is substituted, leaving the rest of the path intact.

[BoboTiG]

Thanks @bysiber!

Can you update the changelog and add a test?

[bysiber]

Added a regression test and a changelog entry. The test creates a directory tree where the directory name appears twice in the path (e.g. data/data/file.txt) and verifies only the prefix gets swapped.