Initial commit: Nextcloud Notes Tauri app with WYSIWYG editor

Features:
- WYSIWYG markdown editor with TipTap
- Manual save with unsaved changes indicator
- Auto-title derivation from first line (with manual override)
- Manual sync button with visual feedback
- Auto-sync every 5 minutes
- Full formatting toolbar (bold, italic, headings, lists, code)
- Note creation, editing, deletion
- Search and favorites filter
- Cross-platform desktop app built with Tauri + React + TypeScript

src-tauri/src/lib.rs

@@ -0,0 +1,14 @@
+// Learn more about Tauri commands at https://tauri.app/develop/calling-rust/
+#[tauri::command]
+fn greet(name: &str) -> String {
+    format!("Hello, {}! You've been greeted from Rust!", name)
+}
+
+#[cfg_attr(mobile, tauri::mobile_entry_point)]
+pub fn run() {
+    tauri::Builder::default()
+        .plugin(tauri_plugin_opener::init())
+        .invoke_handler(tauri::generate_handler![greet])
+        .run(tauri::generate_context!())
+        .expect("error while running tauri application");
+}