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

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

backend/crates/domain/src/host.rs

@@ -0,0 +1,55 @@
+//! Host inventory: operating system and installed packages.
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct OsInfo {
+    pub hostname: String,
+    pub name: String,
+    pub version: String,
+    pub kernel: String,
+    pub uptime_secs: u64,
+    pub reboot_required: bool,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum PackageSource {
+    Apt,
+    Snap,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Package {
+    pub name: String,
+    pub source: PackageSource,
+    pub installed: String,
+    /// Newer version available, if any.
+    pub candidate: Option<String>,
+    pub is_security: bool,
+}
+
+impl Package {
+    pub fn is_upgradable(&self) -> bool {
+        self.candidate.is_some()
+    }
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Inventory {
+    pub os: OsInfo,
+    pub packages: Vec<Package>,
+    pub refreshed_at: DateTime<Utc>,
+}
+
+impl Inventory {
+    pub fn upgradable(&self) -> usize {
+        self.packages.iter().filter(|p| p.is_upgradable()).count()
+    }
+    pub fn security_upgrades(&self) -> usize {
+        self.packages
+            .iter()
+            .filter(|p| p.is_upgradable() && p.is_security)
+            .count()
+    }
+}

backend/crates/domain/src/lib.rs

@@ -2,6 +2,7 @@
 //! layer depends on. No I/O here.
 pub mod auth;
 pub mod error;
+pub mod host;
 pub mod jobs;
 pub mod ports;
 pub mod settings;

backend/crates/domain/src/ports.rs

@@ -3,6 +3,7 @@ use async_trait::async_trait;
 use uuid::Uuid;
 
 use crate::auth::{AccessClaims, AuthEvent, RefreshToken};
+use crate::host::{Inventory, OsInfo, Package};
 use crate::jobs::{JobKind, JobRun, JobStatus};
 use crate::settings::SmtpSettings;
 use crate::user::{User, UserUpdate};
@@ -76,3 +77,16 @@ pub trait JobRunRepository: Send + Sync {
     async fn find_running(&self, kind: JobKind) -> Result<Option<JobRun>, DomainError>;
     async fn last_finished(&self, kind: JobKind) -> Result<Option<JobRun>, DomainError>;
 }
+
+/// Reads the state of the Debian host.
+#[async_trait]
+pub trait HostInspector: Send + Sync {
+    async fn os_info(&self) -> Result<OsInfo, DomainError>;
+    async fn packages(&self) -> Result<Vec<Package>, DomainError>;
+}
+
+#[async_trait]
+pub trait InventoryRepository: Send + Sync {
+    async fn save(&self, inventory: &Inventory) -> Result<(), DomainError>;
+    async fn load(&self) -> Result<Option<Inventory>, DomainError>;
+}