* fix: S3 listing NextMarker missing intermediate directory component
When listing with nested prefixes like "character/member/", the NextMarker
was incorrectly constructed as "character/res024/" instead of
"character/member/res024/", causing continuation requests to fail.
Root cause: The code at line 331 was constructing NextMarker as:
nextMarker = requestDir + "/" + nextMarker
This worked when nextMarker already contained the full relative path,
but failed when it was just the entry name from the innermost recursion.
Fix: Include the prefix component when constructing NextMarker:
if prefix != "" {
nextMarker = requestDir + "/" + prefix + "/" + nextMarker
}
This ensures the full path is always constructed correctly for both:
- CommonPrefix entries (directories)
- Regular entries (files)
Also includes fix for cursor.prefixEndsOnDelimiter state leak that was
causing sibling directories to be incorrectly listed.
* test: add regression tests for NextMarker construction
Add comprehensive unit tests to verify NextMarker is correctly constructed
with nested prefixes. Tests cover:
- Regular entries with nested prefix (character/member/res024)
- CommonPrefix entries (directories)
- Edge cases (no requestDir, no prefix, deeply nested)
These tests ensure the fix prevents regression of the bug where
NextMarker was missing intermediate directory components.
