Create NostrEmbed.vue component that renders nostr:note1, nostr:npub1,
and nostr:nevent1 URIs as rich embedded cards. Add bech32 decoder
utility with NIP-19 TLV support for nevent/nprofile. Extend useNostr
with fetchNote() for single-note relay lookups. ChatMessage.vue now
detects and strips nostr URIs, rendering them as inline embed cards.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>