fix(logout): clear stored credentials on logout

Logout was not clearing OAuth tokens or credentials from keyring
and encrypted files. Users had to manually delete files to fully
sign out. Now clears both keyring and file storage.

cc

src-tauri/src/commands_v2.rs

@@ -2476,6 +2476,15 @@ pub async fn v2_logout(
     }
     log::info!("[v2_logout] Legacy client logged out");
 
+    // Step 4: Clear stored credentials (keyring + encrypted files)
+    if let Err(e) = crate::credentials::clear_oauth_token() {
+        log::warn!("[v2_logout] Failed to clear OAuth token: {}", e);
+    }
+    if let Err(e) = crate::credentials::clear_qobuz_credentials() {
+        log::warn!("[v2_logout] Failed to clear credentials: {}", e);
+    }
+    log::info!("[v2_logout] Stored credentials cleared");
+
     Ok(())
 }