feat: Make app fully portable

- Add tauri-plugin-store for portable data storage
- Implement portable data directory (TypoGenie-Data/ next to EXE)
- Configure Rust backend to use EXE-relative paths
- Add store permissions for persistent settings
- Update README with portable badges and documentation
- Document how to build and use the portable EXE
- Zero registry, zero AppData, fully self-contained

src-tauri/src/lib.rs

@@ -1,26 +1,59 @@
-use tauri::Manager;
+use std::path::PathBuf;
+use tauri::{Manager, path::BaseDirectory};
+
+/// Gets the portable data directory (next to the executable)
+fn get_portable_data_dir(app: &tauri::App) -> PathBuf {
+    // Get the directory where the EXE is located
+    if let Ok(exe_dir) = app.path().resolve("", BaseDirectory::Executable) {
+        let portable_dir = exe_dir.join("TypoGenie-Data");
+        // Create the directory if it doesn't exist
+        let _ = std::fs::create_dir_all(&portable_dir);
+        portable_dir
+    } else {
+        // Fallback to app data directory (shouldn't happen)
+        app.path().app_data_dir().unwrap_or_else(|_| PathBuf::from("."))
+    }
+}
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
-  tauri::Builder::default()
-    .plugin(tauri_plugin_dialog::init())
-    .plugin(tauri_plugin_fs::init())
-    .setup(|app| {
-      // Show the main window after setup
-      if let Some(window) = app.get_webview_window("main") {
-        let _ = window.show();
-        let _ = window.set_focus();
-      }
+    tauri::Builder::default()
+        .plugin(tauri_plugin_dialog::init())
+        .plugin(tauri_plugin_fs::init())
+        .plugin(tauri_plugin_store::Builder::default().build())
+        .setup(|app| {
+            // Set up portable data directory
+            let portable_dir = get_portable_data_dir(app);
+            println!("Portable data directory: {:?}", portable_dir);
+            
+            // Store the portable path in app state for frontend access
+            app.manage(PortableDataDir(portable_dir));
 
-      if cfg!(debug_assertions) {
-        app.handle().plugin(
-          tauri_plugin_log::Builder::default()
-            .level(log::LevelFilter::Info)
-            .build(),
-        )?;
-      }
-      Ok(())
-    })
-    .run(tauri::generate_context!())
-    .expect("error while running tauri application");
+            // Show the main window after setup
+            if let Some(window) = app.get_webview_window("main") {
+                let _ = window.show();
+                let _ = window.set_focus();
+            }
+
+            if cfg!(debug_assertions) {
+                app.handle().plugin(
+                    tauri_plugin_log::Builder::default()
+                        .level(log::LevelFilter::Info)
+                        .build(),
+                )?;
+            }
+            Ok(())
+        })
+        .invoke_handler(tauri::generate_handler![get_data_dir])
+        .run(tauri::generate_context!())
+        .expect("error while running tauri application");
+}
+
+/// Structure to hold the portable data directory path
+struct PortableDataDir(PathBuf);
+
+/// Command to get the portable data directory from the frontend
+#[tauri::command]
+fn get_data_dir(state: tauri::State<PortableDataDir>) -> String {
+    state.0.to_string_lossy().to_string()
 }