feat: Routing fuer Workspace-Auswahl und Editor aufbauen

Zwei Router: WorkspaceRoute (Workspace anlegen/oeffnen) und EditorRoute
(Home/Editor), umgeschaltet ueber ein Signal in App.

Die Navigationslinks werden nicht mehr einzeln ausgeschrieben, sondern aus
dem Routen-Enum erzeugt (strum EnumIter). Die Beschriftung haengt per
#[strum(message = "...")] an der Variante selbst, damit eine neue Route nur
an einer Stelle gepflegt werden muss.

CustomLink kapselt Link und markiert den aktiven Eintrag ueber active_class
statt ueber eigenen Klick-Zustand - das funktioniert auch bei Deep-Links und
dem Zurueck-Button.

src/main.rs

@@ -0,0 +1,43 @@
+mod views;
+mod components;
+
+use dioxus::prelude::*;
+use crate::views::editor::dionotes_editor::EditorRoute;
+use crate::views::workspace_selector::selector::WorkspaceRoute;
+
+const FAVICON: Asset = asset!("/assets/favicon.ico");
+
+// Linked individually rather than via @import in a single entry file: asset!()
+// only emits files it is given by name, so an @import chain would 404 at runtime.
+// Order matters — tokens, then baseline, then layout, then components.
+const TAILWIND_CSS: Asset = asset!("/assets/tailwind.css");
+const TOKENS_CSS: Asset = asset!("/assets/css/tokens.css");
+const BASE_CSS: Asset = asset!("/assets/css/base.css");
+const LAYOUT_CSS: Asset = asset!("/assets/css/layout.css");
+const COMPONENTS_CSS: Asset = asset!("/assets/css/components.css");
+
+fn main() {
+    launch(App);
+}
+
+#[component]
+fn App() -> Element {
+    let workspace_selected: Signal<bool> = use_signal(|| false);
+    rsx! {
+        document::Link { rel: "icon", href: FAVICON }
+        // Tailwind first: its preflight lives in @layer base, our unlayered
+        // rules win the cascade regardless, but this keeps source order honest.
+        document::Link { rel: "stylesheet", href: TAILWIND_CSS }
+        document::Link { rel: "stylesheet", href: TOKENS_CSS }
+        document::Link { rel: "stylesheet", href: BASE_CSS }
+        document::Link { rel: "stylesheet", href: LAYOUT_CSS }
+        document::Link { rel: "stylesheet", href: COMPONENTS_CSS }
+        if workspace_selected() {
+            Router::<EditorRoute> {}
+        } else {
+            Router::<WorkspaceRoute> {}
+        }
+    }
+}
+
+