feat(kon): scaffold hybrid modular workspace

- Cargo workspace with 6 domain crates: core, audio, transcription, ai-formatting, storage, cloud-providers
- Minimal Tauri shell (lib.rs + main.rs) with plugin registration
- Svelte 5 frontend copied from Ramble v0.2
- All crates compile as empty stubs
- App identifier: uk.co.corbel.kon

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src-tauri/src/lib.rs

@@ -0,0 +1,9 @@
+#[cfg_attr(mobile, tauri::mobile_entry_point)]
+pub fn run() {
+    tauri::Builder::default()
+        .plugin(tauri_plugin_opener::init())
+        .plugin(tauri_plugin_dialog::init())
+        .plugin(tauri_plugin_global_shortcut::Builder::new().build())
+        .run(tauri::generate_context!())
+        .expect("error while running Kon");
+}