Root cause: NUser's extension signer exposes .nip44 as a getter that calls
.nostr (window.nostr) and THROWS when the extension isn't present. Any
synchronous access during render crashes the whole tree — the actual culprit
was useStash's `isEncryptionAvailable: !!user?.signer?.nip44` in its return
object, evaluated every render even when logged out.
- Add src/lib/signerCapabilities.ts: hasNip44/hasNip04 helpers that determine
capability via login type + direct window.nostr probe (no throwing getter).
- useStash: use the helper for hasNip44 + isEncryptionAvailable
- useDirectMessages: replace all render-path `enabled: !!user?.signer?.nip44`
with a pre-computed nip44Available across all 4 conversation hooks
- CrewChat, CrewRequestToJoin, ConversationPage, DirectMessagesPage,
ContactsPage: use the safe helper in render/guard paths
Async accesses (inside queryFn/callbacks) are left as-is — they reject
gracefully within react-query and never crash render.
Co-authored-by: shakespeare.diy <assistant@shakespeare.diy>
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