structural refactor and codebase improvements

crates/application/src/users/get_federated_profile.rs

@@ -0,0 +1,31 @@
+use domain::errors::DomainError;
+use domain::models::FederatedProfile;
+use uuid::Uuid;
+
+use crate::users::deps::GetFederatedProfileDeps;
+
+/// Looks up a federated (remote) profile by synthetic user id — the fallback
+/// path `get_user_profile` (`handlers/users.rs`) takes when the local-profile
+/// lookup comes back `NotFound`.
+///
+/// Federation being disabled (`deps.federated_profile` is `None`) collapses to
+/// `Ok(None)`, the same value a present-but-empty lookup would return. That's
+/// deliberate: the handler's `if let Ok(Some(fed)) = ...` treats "port absent",
+/// "call returned `Ok(None)`", and "call returned `Err`" identically — all three
+/// fall through to a 404 — and this use case must not make any of those three
+/// distinguishable to a caller that cannot act on the difference. An `Err` from
+/// the port is propagated unchanged; the swallow stays at the handler, exactly
+/// where it already was.
+pub async fn execute(
+    deps: &GetFederatedProfileDeps,
+    user_id: Uuid,
+) -> Result<Option<FederatedProfile>, DomainError> {
+    match &deps.federated_profile {
+        Some(fed_query) => fed_query.get_federated_profile(user_id).await,
+        None => Ok(None),
+    }
+}
+
+#[cfg(test)]
+#[path = "tests/get_federated_profile.rs"]
+mod tests;