WP-10: contract and failing tests for OS and package inventory

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

backend/crates/application/src/test_fakes.rs

@@ -305,3 +305,66 @@ pub fn smtp() -> SmtpSettings {
         notify_to: vec!["ops@example.com".into()],
     }
 }
+
+use domain::host::{Inventory, OsInfo, Package, PackageSource};
+use domain::ports::{HostInspector, InventoryRepository};
+
+pub struct FakeInspector {
+    pub fail: bool,
+}
+
+#[async_trait]
+impl HostInspector for FakeInspector {
+    async fn os_info(&self) -> Result<OsInfo, DomainError> {
+        if self.fail {
+            return Err(DomainError::Unavailable("host down".into()));
+        }
+        Ok(OsInfo {
+            hostname: "srv".into(),
+            name: "Debian GNU/Linux 12 (bookworm)".into(),
+            version: "12".into(),
+            kernel: "6.1.0-42-amd64".into(),
+            uptime_secs: 3600,
+            reboot_required: true,
+        })
+    }
+    async fn packages(&self) -> Result<Vec<Package>, DomainError> {
+        Ok(vec![
+            Package {
+                name: "bash".into(),
+                source: PackageSource::Apt,
+                installed: "5.2".into(),
+                candidate: None,
+                is_security: false,
+            },
+            Package {
+                name: "openssl".into(),
+                source: PackageSource::Apt,
+                installed: "3.0.1".into(),
+                candidate: Some("3.0.2".into()),
+                is_security: true,
+            },
+            Package {
+                name: "microk8s".into(),
+                source: PackageSource::Snap,
+                installed: "v1.32.13".into(),
+                candidate: None,
+                is_security: false,
+            },
+        ])
+    }
+}
+
+#[derive(Default)]
+pub struct MemInventory(pub Mutex<Option<Inventory>>);
+
+#[async_trait]
+impl InventoryRepository for MemInventory {
+    async fn save(&self, inventory: &Inventory) -> Result<(), DomainError> {
+        *self.0.lock().unwrap() = Some(inventory.clone());
+        Ok(())
+    }
+    async fn load(&self) -> Result<Option<Inventory>, DomainError> {
+        Ok(self.0.lock().unwrap().clone())
+    }
+}