feat: config vaults par défaut au premier lancement

- Détecte config.vaults vide → premier lancement
- Crée %USERPROFILE%\voute_obsidian\ automatiquement
- Ajoute deux vaults: 'Dossier' (%USERPROFILE%) et 'Obsidian' (voute_obsidian)
- vault_path = USERPROFILE pour le sélecteur de dossier

desktop/src/main.rs

@@ -388,7 +388,37 @@ fn main() {
     info!("Exe dir: {}", exe_dir.display());
 
     // Load config for window state
-    let config = load_config();
+    let mut config = load_config();
+
+    // First run: create default vault config
+    if config.vaults.is_empty() {
+        info!("First run — creating default vault configuration");
+        let userprofile = std::env::var("USERPROFILE").unwrap_or_else(|_| "C:\\Users\\Default".to_string());
+        let vault_dir = std::path::PathBuf::from(&userprofile).join("voute_obsidian");
+
+        // Create the vault directory if it doesn't exist
+        if !vault_dir.exists() {
+            if let Err(e) = fs::create_dir_all(&vault_dir) {
+                error!("Failed to create default vault dir {}: {}", vault_dir.display(), e);
+            } else {
+                info!("Created default vault dir: {}", vault_dir.display());
+            }
+        }
+
+        config.vaults = vec![
+            VaultConfig {
+                name: "Dossier".to_string(),
+                path: userprofile.clone(),
+            },
+            VaultConfig {
+                name: "Obsidian".to_string(),
+                path: vault_dir.to_string_lossy().to_string(),
+            },
+        ];
+        config.vault_path = Some(userprofile);
+        save_config(&config);
+        info!("Default vault config saved");
+    }
 
     // Spawn Python backend
     let backend = match spawn_backend(&exe_dir) {