WP-02: contracts and failing tests for settings, mail, jobs and scheduler

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

backend/crates/application/src/settings_service.rs

@@ -0,0 +1,58 @@
+use std::sync::Arc;
+
+use domain::jobs::JobKind;
+use domain::ports::{Cipher, Mailer, SettingsRepository};
+use domain::settings::SmtpSettings;
+use domain::DomainError;
+
+pub struct SettingsService {
+    repo: Arc<dyn SettingsRepository>,
+    cipher: Arc<dyn Cipher>,
+    mailer: Arc<dyn Mailer>,
+}
+
+impl SettingsService {
+    pub fn new(
+        repo: Arc<dyn SettingsRepository>,
+        cipher: Arc<dyn Cipher>,
+        mailer: Arc<dyn Mailer>,
+    ) -> Self {
+        let _ = (&repo, &cipher, &mailer);
+        Self {
+            repo,
+            cipher,
+            mailer,
+        }
+    }
+
+    pub async fn smtp(&self) -> Result<Option<SmtpSettings>, DomainError> {
+        todo!()
+    }
+
+    pub async fn set_smtp(&self, _smtp: SmtpSettings) -> Result<(), DomainError> {
+        todo!()
+    }
+
+    /// Send a mail to the configured recipients (or `to` if given) using the stored SMTP settings.
+    pub async fn send_mail(
+        &self,
+        _to: Option<Vec<String>>,
+        _subject: &str,
+        _body: &str,
+    ) -> Result<(), DomainError> {
+        todo!()
+    }
+
+    /// Cron expression (6 fields, seconds first) for a scheduled job kind, or None if disabled.
+    pub async fn schedule(&self, _kind: JobKind) -> Result<Option<String>, DomainError> {
+        todo!()
+    }
+
+    pub async fn set_schedule(
+        &self,
+        _kind: JobKind,
+        _cron: Option<String>,
+    ) -> Result<(), DomainError> {
+        todo!()
+    }
+}