Threads serves actors at threads.net but their id field uses www.threads.net.
Extract apex_domain() helper and fall back to apex comparison when the
strict verify_domains_match check fails.
Add display_name field to DbActor, populated from AP Person.name in
from_json. Expose LookedUpActor type and lookup_actor_by_handle method
on ActivityPubService — uses the existing signed webfinger_https path
so strict instances (Threads, etc.) return full actor data.
