resolve_profile returned 404 when the requested handle had no
posts in the local index — true for every local-PDS account
that hasn't yet had its posts ingested through the Jetstream
consumer. The UI then surfaced this as a raw 'err: appview:
profile returned 404' toast instead of an empty profile.
Return a profile row with the requested handle and zero counts
instead. The DID is left empty; the UI's 'copy did' button just
copies an empty string and the header falls back to the handle,
which is the right behaviour for a never-indexed local user.