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/delete_profile.rs

@@ -15,3 +15,7 @@ pub async fn execute(ctx: &AppContext, cmd: DeleteImportProfileCommand) -> Resul
         .ok_or_else(|| DomainError::NotFound("import profile".into()))?;
     ctx.repos.import_profile.delete(&profile_id).await
 }
+
+#[cfg(test)]
+#[path = "tests/delete_profile.rs"]
+mod tests;