feat: Add desktop client and update workspace

Adds the desktop client as a new workspace member and includes its
initial
Cargo.toml and main.rs files. This lays the groundwork for the desktop
application's user interface and integration with the common library.

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = ["server", "doctate-common"]
+members = ["server", "doctate-common", "client-desktop"]
 resolver = "3"
 
 [workspace.package]

client-desktop/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "doctate-desktop"
+version.workspace = true
+edition.workspace = true
+description = "Desktop dictation client for the doctate medical dictation system"
+
+[dependencies]
+doctate-common = { path = "../doctate-common" }
+eframe = "0.28"
+tracing = { workspace = true }
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }

client-desktop/src/main.rs

@@ -0,0 +1,42 @@
+use eframe::egui;
+use tracing::info;
+use tracing_subscriber::EnvFilter;
+
+fn main() -> eframe::Result {
+    tracing_subscriber::fmt()
+        .with_env_filter(
+            EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("doctate_desktop=info")),
+        )
+        .init();
+
+    info!("starting doctate-desktop");
+
+    let options = eframe::NativeOptions {
+        viewport: egui::ViewportBuilder::default()
+            .with_inner_size([320.0, 200.0])
+            .with_resizable(false),
+        ..Default::default()
+    };
+
+    eframe::run_native(
+        "doctate",
+        options,
+        Box::new(|_cc| Ok(Box::<DoctateApp>::default())),
+    )
+}
+
+#[derive(Default)]
+struct DoctateApp;
+
+impl eframe::App for DoctateApp {
+    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+        egui::CentralPanel::default().show(ctx, |ui| {
+            ui.vertical_centered(|ui| {
+                ui.add_space(20.0);
+                ui.heading("doctate");
+                ui.add_space(20.0);
+                ui.label("Skelett — Buttons kommen in Schritt 4e.");
+            });
+        });
+    }
+}