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/jobs.rs

@@ -0,0 +1,73 @@
+//! Job runner: starts a handler for a job kind, persists its log and result.
+use std::collections::HashMap;
+use std::sync::Arc;
+
+use async_trait::async_trait;
+use domain::jobs::{JobKind, JobRun};
+use domain::ports::JobRunRepository;
+use domain::DomainError;
+use uuid::Uuid;
+
+/// Sink for log lines of a running job.
+#[async_trait]
+pub trait JobLog: Send + Sync {
+    async fn line(&self, text: &str);
+}
+
+#[async_trait]
+pub trait JobHandler: Send + Sync {
+    async fn run(&self, params: Option<String>, log: &dyn JobLog) -> Result<(), String>;
+}
+
+pub struct JobRunner {
+    runs: Arc<dyn JobRunRepository>,
+    handlers: HashMap<JobKind, Arc<dyn JobHandler>>,
+}
+
+impl JobRunner {
+    pub fn new(runs: Arc<dyn JobRunRepository>) -> Self {
+        Self {
+            runs,
+            handlers: HashMap::new(),
+        }
+    }
+
+    pub fn register(mut self, kind: JobKind, handler: Arc<dyn JobHandler>) -> Self {
+        self.handlers.insert(kind, handler);
+        self
+    }
+
+    pub fn kinds(&self) -> Vec<JobKind> {
+        let mut k: Vec<_> = self.handlers.keys().copied().collect();
+        k.sort_by_key(|k| k.as_str());
+        k
+    }
+
+    /// Start a job in the background. Fails with `Conflict` if the kind is already running.
+    pub async fn start(
+        &self,
+        _kind: JobKind,
+        _params: Option<String>,
+        _triggered_by: &str,
+    ) -> Result<JobRun, DomainError> {
+        todo!()
+    }
+
+    /// Run a job and wait for it to finish (used by tests and the scheduler).
+    pub async fn run_and_wait(
+        &self,
+        _kind: JobKind,
+        _params: Option<String>,
+        _triggered_by: &str,
+    ) -> Result<JobRun, DomainError> {
+        todo!()
+    }
+
+    pub async fn get(&self, _id: Uuid) -> Result<JobRun, DomainError> {
+        todo!()
+    }
+
+    pub async fn list(&self, _limit: u32) -> Result<Vec<JobRun>, DomainError> {
+        todo!()
+    }
+}