feat(gui): D-Bus client wrapper around AuthForge interface

gui/src/bus.rs

@@ -0,0 +1,56 @@
+//! D-Bus client for the GUI. zbus runs on the workspace tokio runtime; the
+//! runtime guard installed in `main` keeps the runtime context alive for the
+//! lifetime of `app.run()`. Closures dispatch async work via
+//! `glib::MainContext::spawn_local`, which polls the future on the GTK main
+//! thread; tokio's reactor wakes the future when zbus I/O is ready.
+
+use authforge_common::types::Credential;
+
+const BUS_NAME: &str = "io.dangerousthings.AuthForge";
+const OBJECT_PATH: &str = "/io/dangerousthings/AuthForge";
+const IFACE: &str = "io.dangerousthings.AuthForge1";
+
+#[derive(Clone)]
+#[allow(dead_code)] // wired through keys_page.rs / enroll_dialog.rs in Tasks 4-6.
+pub(crate) struct Daemon {
+    proxy: zbus::Proxy<'static>,
+}
+
+#[allow(dead_code)] // wired through keys_page.rs / enroll_dialog.rs in Tasks 4-6.
+impl Daemon {
+    pub async fn connect() -> zbus::Result<Self> {
+        let conn = zbus::Connection::system().await?;
+        // Mirror the CLI's known-working pattern; `Proxy::new_owned` returns a
+        // Proxy<'static> owning its connection so `Daemon` can be passed
+        // around freely.
+        let proxy = zbus::Proxy::new_owned(conn, BUS_NAME, OBJECT_PATH, IFACE).await?;
+        Ok(Self { proxy })
+    }
+
+    pub async fn list_credentials(&self, user: &str) -> zbus::Result<Vec<Credential>> {
+        self.proxy.call("ListCredentials", &(user,)).await
+    }
+
+    pub async fn enroll_own(&self, user: &str, nickname: &str) -> zbus::Result<Credential> {
+        self.proxy.call("EnrollOwn", &(user, nickname)).await
+    }
+
+    pub async fn remove_own(&self, user: &str, cred_id: &str) -> zbus::Result<()> {
+        self.proxy.call("RemoveOwn", &(user, cred_id)).await
+    }
+
+    /// Subscribes to `EnrollmentFailed`. The returned stream is alive as long
+    /// as the caller holds it; the touch dialog drops it when it closes. We
+    /// don't subscribe to `EnrollmentSucceeded` because the call's return
+    /// value carries the new `Credential` — the source of truth for success.
+    pub async fn subscribe_enrollment_failed(
+        &self,
+    ) -> zbus::Result<zbus::proxy::SignalStream<'static>> {
+        self.proxy.receive_signal("EnrollmentFailed").await
+    }
+}
+
+#[allow(dead_code)] // wired through keys_page.rs in Task 4.
+pub(crate) fn current_user() -> String {
+    std::env::var("USER").unwrap_or_else(|_| "unknown".into())
+}

gui/src/main.rs

@@ -1,6 +1,7 @@
 use adw::prelude::*;
 use gtk::glib;
 
+mod bus;
 mod error;
 
 const APP_ID: &str = "io.dangerousthings.AuthForge";