feat(db): users table + repository (create/by_id/by_email/list), audited

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/db/tests/users.rs

@@ -0,0 +1,100 @@
+use db::{Db, audit, users};
+use domain::{AuditAction, AuditActor, Email, NewUser, Role};
+use sqlx::PgPool;
+
+fn new_user(email: &str, role: Role) -> NewUser {
+    NewUser {
+        email: Email::parse(email).unwrap(),
+        password_hash: "$argon2id$dummy".to_owned(),
+        role,
+    }
+}
+
+#[sqlx::test]
+async fn create_then_fetch_by_id_and_email(pool: PgPool) {
+    let db = Db::from_pool(pool);
+
+    let mut tx = db.pool().begin().await.unwrap();
+    let id = users::create_user(
+        &mut tx,
+        AuditActor::System,
+        &new_user("anna@example.com", Role::Admin),
+    )
+    .await
+    .unwrap();
+    tx.commit().await.unwrap();
+
+    let user = users::user_by_id(db.pool(), id).await.unwrap().unwrap();
+    assert_eq!(user.email.as_str(), "anna@example.com");
+    assert_eq!(user.role, Role::Admin);
+
+    let (by_email, hash) = users::credentials_by_email(db.pool(), "anna@example.com")
+        .await
+        .unwrap()
+        .unwrap();
+    assert_eq!(by_email.id, id);
+    assert_eq!(hash, "$argon2id$dummy");
+}
+
+#[sqlx::test]
+async fn create_user_audits_email_and_role_but_never_the_hash(pool: PgPool) {
+    let db = Db::from_pool(pool);
+    let mut tx = db.pool().begin().await.unwrap();
+    let id = users::create_user(
+        &mut tx,
+        AuditActor::System,
+        &new_user("anna@example.com", Role::Editor),
+    )
+    .await
+    .unwrap();
+    tx.commit().await.unwrap();
+
+    let history = audit::history_for(db.pool(), "user", id.to_uuid())
+        .await
+        .unwrap();
+    assert_eq!(history.len(), 1);
+    assert_eq!(history[0].action, AuditAction::Created);
+    let mut fields: Vec<&str> = history[0]
+        .changes
+        .iter()
+        .map(|c| c.field.as_str())
+        .collect();
+    fields.sort_unstable();
+    assert_eq!(fields, vec!["email", "role"]);
+}
+
+#[sqlx::test]
+async fn missing_email_returns_none(pool: PgPool) {
+    let db = Db::from_pool(pool);
+    assert!(
+        users::credentials_by_email(db.pool(), "nobody@example.com")
+            .await
+            .unwrap()
+            .is_none()
+    );
+}
+
+#[sqlx::test]
+async fn list_users_is_ordered_by_email(pool: PgPool) {
+    let db = Db::from_pool(pool);
+    let mut tx = db.pool().begin().await.unwrap();
+    users::create_user(
+        &mut tx,
+        AuditActor::System,
+        &new_user("zoe@example.com", Role::Editor),
+    )
+    .await
+    .unwrap();
+    users::create_user(
+        &mut tx,
+        AuditActor::System,
+        &new_user("amy@example.com", Role::Admin),
+    )
+    .await
+    .unwrap();
+    tx.commit().await.unwrap();
+
+    let users = users::list_users(db.pool()).await.unwrap();
+    let emails: Vec<&str> = users.iter().map(|u| u.email.as_str()).collect();
+    assert_eq!(emails, vec!["amy@example.com", "zoe@example.com"]);
+}