Fix: visitors can reply to the site owner's own comments
The visitor 'reply via the fediverse' button only rendered on !mine thread
nodes, so the site's own comments offered visitors no action at all: you could
not answer the author's comment from your own instance (reported by Robin on
deno.klonkt.com, replying as sound-fabrics.com). The else-if now also renders
for mine-nodes with a noteId; owners never reach it (their mine/!mine branches
match first) and the own-reply note URI (/ap/notes/<id>) is AP-dereferenceable,
verified. Visitor view verified: the owner's comment now carries the button
with its note URI.
Co-Authored-By: Claude Opus 4.8 <noreply@…>