fix: wire single-instance plugin for OAuth deep-link callback

The Maximus Account sign-in flow was broken in v0.7.0: clicking "Sign in"
opened Logto in the browser, but when the OAuth2 callback fired
simpl-resultat://auth/callback?code=..., the OS launched a second app
instance instead of routing the URL to the running one. The second
instance had no PKCE verifier in memory, and the original instance
never received the deep-link event, leaving it stuck in "loading".

Fix: register tauri-plugin-single-instance (with the deep-link feature)
as the first plugin. It forwards the callback URL to the existing
process, which triggers the existing deep-link://new-url listener and
completes the token exchange.

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

CHANGELOG.fr.md

@@ -2,6 +2,11 @@
 
 ## [Non publié]
 
+## [0.7.1] - 2026-04-13
+
+### Corrigé
+- Connexion Compte Maximus : le callback OAuth2 revient maintenant correctement dans l'instance en cours au lieu de lancer une deuxième instance et de laisser l'app d'origine bloquée en « chargement » (#51, #65)
+
 ## [0.7.0] - 2026-04-11
 
 ### Ajouté

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## [Unreleased]
 
+## [0.7.1] - 2026-04-13
+
+### Fixed
+- Maximus Account sign-in: the OAuth2 callback now correctly returns to the running app instead of launching a second instance and leaving the original one stuck in "loading" (#51, #65)
+
 ## [0.7.0] - 2026-04-11
 
 ### Added

package.json

@@ -1,7 +1,7 @@
 {
   "name": "simpl_result_scaffold",
   "private": true,
-  "version": "0.7.0",
+  "version": "0.7.1",
   "license": "GPL-3.0-only",
   "type": "module",
   "scripts": {

src-tauri/Cargo.lock

@@ -4280,7 +4280,7 @@ checksum = "e320a6c5ad31d271ad523dcf3ad13e2767ad8b1cb8f047f75a8aeaf8da139da2"
 
 [[package]]
 name = "simpl-result"
-version = "0.6.7"
+version = "0.7.1"
 dependencies = [
  "aes-gcm",
  "argon2",
@@ -4303,6 +4303,7 @@ dependencies = [
  "tauri-plugin-dialog",
  "tauri-plugin-opener",
  "tauri-plugin-process",
+ "tauri-plugin-single-instance",
  "tauri-plugin-sql",
  "tauri-plugin-updater",
  "tokio",
@@ -5055,6 +5056,22 @@ dependencies = [
  "tauri-plugin",
 ]
 
+[[package]]
+name = "tauri-plugin-single-instance"
+version = "2.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a33a5b7d78f0dec4406b003ea87c40bf928d801b6fd9323a556172c91d8712c1"
+dependencies = [
+ "serde",
+ "serde_json",
+ "tauri",
+ "tauri-plugin-deep-link",
+ "thiserror 2.0.18",
+ "tracing",
+ "windows-sys 0.60.2",
+ "zbus",
+]
+
 [[package]]
 name = "tauri-plugin-sql"
 version = "2.3.2"

src-tauri/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "simpl-result"
-version = "0.7.0"
+version = "0.7.1"
 description = "Personal finance management app"
 license = "GPL-3.0-only"
 authors = ["you"]
@@ -26,6 +26,7 @@ tauri-plugin-dialog = "2"
 tauri-plugin-updater = "2"
 tauri-plugin-process = "2"
 tauri-plugin-deep-link = "2"
+tauri-plugin-single-instance = { version = "2", features = ["deep-link"] }
 libsqlite3-sys = { version = "0.30", features = ["bundled"] }
 rusqlite = { version = "0.32", features = ["bundled"] }
 serde = { version = "1", features = ["derive"] }

src-tauri/src/lib.rs

@@ -2,7 +2,7 @@ mod commands;
 mod database;
 
 use std::sync::Mutex;
-use tauri::{Emitter, Listener};
+use tauri::{Emitter, Listener, Manager};
 use tauri_plugin_sql::{Migration, MigrationKind};
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
@@ -84,6 +84,14 @@ pub fn run() {
     ];
 
     tauri::Builder::default()
+        // Single-instance plugin MUST be registered first. With the `deep-link`
+        // feature, it forwards `simpl-resultat://` URLs to the running instance
+        // so the OAuth2 callback reaches the process that holds the PKCE verifier.
+        .plugin(tauri_plugin_single_instance::init(|app, _argv, _cwd| {
+            if let Some(window) = app.get_webview_window("main") {
+                let _ = window.set_focus();
+            }
+        }))
         .manage(commands::auth_commands::OAuthState {
             code_verifier: Mutex::new(None),
         })

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "Simpl Resultat",
-  "version": "0.7.0",
+  "version": "0.7.1",
   "identifier": "com.simpl.resultat",
   "build": {
     "beforeDevCommand": "npm run dev",