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/goals/tests/list.rs

@@ -0,0 +1,47 @@
+use uuid::Uuid;
+
+use crate::goals::{commands::CreateGoalCommand, create, list, queries::ListGoalsQuery};
+use crate::test_helpers::TestContextBuilder;
+
+#[tokio::test]
+async fn returns_empty_when_no_goals() {
+    let ctx = TestContextBuilder::new().build();
+    let result = list::execute(
+        &ctx,
+        ListGoalsQuery {
+            user_id: Uuid::nil(),
+        },
+    )
+    .await
+    .unwrap();
+
+    assert!(result.is_empty());
+}
+
+#[tokio::test]
+async fn returns_all_goals_for_user() {
+    let ctx = TestContextBuilder::new().build();
+    for year in [2023, 2024, 2025] {
+        create::execute(
+            &ctx,
+            CreateGoalCommand {
+                user_id: Uuid::nil(),
+                year,
+                target_count: 10,
+            },
+        )
+        .await
+        .unwrap();
+    }
+
+    let result = list::execute(
+        &ctx,
+        ListGoalsQuery {
+            user_id: Uuid::nil(),
+        },
+    )
+    .await
+    .unwrap();
+
+    assert_eq!(result.len(), 3);
+}