fix: more appropriate http signature errors

if we cant fetch from db its our fault (500), if we cant fetch your
actor its your fault (4xx)

upub/routes/src/auth.rs

@@ -1,7 +1,7 @@
 use axum::{extract::{FromRef, FromRequestParts}, http::{header, request::Parts}};
 use sea_orm::{ColumnTrait, Condition, EntityTrait, QueryFilter};
 use httpsign::HttpSignature;
-use upub::traits::Fetcher;
+use upub::traits::{fetch::PullError, Fetcher};
 
 use crate::ApiError;
 
@@ -120,8 +120,10 @@ where
 				.next().ok_or(ApiError::bad_request())?
 				.to_string();
 
-			let user = ctx.fetch_user(&user_id, ctx.db()).await?;
+			match ctx.fetch_user(&user_id, ctx.db()).await {
-
+				Err(PullError::Database(x)) => return Err(PullError::Database(x).into()),
+				Err(_) => tracing::debug!("could not fetch {user_id} to verify signature"),
+				Ok(user) => {
 					let valid = http_signature
 						.build_from_parts(parts)
 						.verify(&user.public_key)?;
@@ -135,6 +137,9 @@ where
 						.await?
 						.ok_or_else(ApiError::internal_server_error)?; // user but not their domain???
 					identity = Identity::Remote { user: user.id, domain: user.domain, internal };
+				},
+			}
+
 		}
 
 		Ok(AuthIdentity(identity))