add 400+ unit tests for domain and application layers

Extract ReviewLogger trait to decouple import/integrations
from diary::log_review (cross-module coupling smell).

Add in-memory fakes for all repository ports, enabling
isolated testing of every use case module without a database.

Coverage: domain+application 22% → 80%, 427 tests.

crates/application/src/import/tests/delete_profile.rs

@@ -0,0 +1,26 @@
+use std::sync::Arc;
+
+use domain::testing::InMemoryImportProfileRepository;
+use uuid::Uuid;
+
+use crate::import::{commands::DeleteImportProfileCommand, delete_profile};
+use crate::test_helpers::TestContextBuilder;
+
+#[tokio::test]
+async fn fails_when_profile_not_found() {
+    let profiles = InMemoryImportProfileRepository::new();
+    let ctx = TestContextBuilder::new()
+        .with_import_profiles(Arc::clone(&profiles) as _)
+        .build();
+
+    let result = delete_profile::execute(
+        &ctx,
+        DeleteImportProfileCommand {
+            user_id: Uuid::new_v4(),
+            profile_id: Uuid::new_v4(),
+        },
+    )
+    .await;
+
+    assert!(result.is_err());
+}