The alt-tag fallback shipped in 9813a226 let several display paths fall
through to other tags (title, name, summary, description, d) or to the
raw content when alt was absent. For an unknown kind like attestr.xyz
(31871), that surfaced the opaque d-tag identifier
'e5272de9:289bce03a0b7:1777206698' as the preview and leaked raw content
into the hover-card reply indicator — both worse than the 'This event
kind is not supported' tombstone the feature was meant to produce.
Tighten the fallback everywhere an unknown kind might render:
- getEventFallbackText: only the NIP-31 alt tag; no title/name/d.
- CommentContext.getEventDisplayName: known kinds keep title/name/d,
unknown kinds consider only alt. getKindLabel returns 'an unsupported
event' instead of 'a post', so 'Commenting on ...' never implies the
root is a text note.
- EmbeddedNote tagMeta: alt only, no title/name/description fallback.
- ExternalContentHeader.AddressableEventPreview: drop d-tag fallback.
- EmbeddedNaddr: gate rich title/description/content rendering behind
a known-kind check; unknown kinds render UnknownKindContent instead
of extractMetadata, which was leaking plaintext content as the
description when the body wasn't JSON.
Regression-of: 9813a226
Alex Gleason
cf2f466772