Add Sign Up functionality to desktop app (#5244)

# Description of Changes
Adds Sign Up with email to desktop app. SSO sign up will come in a
future PR.

frontend/src-tauri/src/lib.rs

@@ -1,4 +1,4 @@
-use tauri::{Manager, RunEvent, WindowEvent, Emitter};
+use tauri::{AppHandle, Emitter, Manager, RunEvent, WindowEvent};
 
 mod utils;
 mod commands;
@@ -28,6 +28,17 @@ use commands::{
 };
 use state::connection_state::AppConnectionState;
 use utils::{add_log, get_tauri_logs};
+use tauri_plugin_deep_link::DeepLinkExt;
+
+fn dispatch_deep_link(app: &AppHandle, url: &str) {
+  add_log(format!("🔗 Dispatching deep link: {}", url));
+  let _ = app.emit("deep-link", url.to_string());
+
+  if let Some(window) = app.get_webview_window("main") {
+    let _ = window.set_focus();
+    let _ = window.unminimize();
+  }
+}
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
@@ -42,6 +53,7 @@ pub fn run() {
     .plugin(tauri_plugin_fs::init())
     .plugin(tauri_plugin_http::init())
     .plugin(tauri_plugin_store::Builder::new().build())
+    .plugin(tauri_plugin_deep_link::init())
     .manage(AppConnectionState::default())
     .plugin(tauri_plugin_single_instance::init(|app, args, _cwd| {
       // This callback runs when a second instance tries to start
@@ -78,6 +90,29 @@ pub fn run() {
         }
       }
 
+      {
+        let app_handle = app.handle();
+        // On macOS the plugin registers schemes via bundle metadata, so runtime registration is required only on Windows/Linux
+        #[cfg(any(target_os = "linux", target_os = "windows"))]
+        if let Err(err) = app_handle.deep_link().register_all() {
+          add_log(format!("⚠️ Failed to register deep link handler: {}", err));
+        }
+
+        if let Ok(Some(urls)) = app_handle.deep_link().get_current() {
+          let initial_handle = app_handle.clone();
+          for url in urls {
+            dispatch_deep_link(&initial_handle, url.as_str());
+          }
+        }
+
+        let event_app_handle = app_handle.clone();
+        app_handle.deep_link().on_open_url(move |event| {
+          for url in event.urls() {
+            dispatch_deep_link(&event_app_handle, url.as_str());
+          }
+        });
+      }
+
       // Start backend immediately, non-blocking
       let app_handle = app.handle().clone();