The adapter facade is ~6.6k lines; new behaviour belongs in a topical sibling per the
facade+siblings layout. expand_link_entities() now lives in telegram_entities.py and
reuses the encode/decode UTF-16 slicing the adapter already uses for entity spans.
Also: skip inlining when the anchor text already is the URL (no 'url (url)' duplication),
trim the test file to the invariants and point it at the sibling.
d7ceee19a8