FOREIGN KEY constraint failed when Panels iOS sends bookmarks/browser settings via OPDS

**Description:** When using Panels (iOS OPDS client) to stream comics, Codex repeatedly crashes with a FOREIGN KEY constraint failed error when trying to save bookmarks or browser settings. The error occurs every few seconds in an endless loop and makes OPDS unusable. Steps to reproduce: **Set up Codex with OPDS v1.2** Connect Panels (iOS) via OPDS Open any comic subfolder or start reading a comic Codex immediately starts throwing FOREIGN KEY constraint failed on bookmarks_bookmark or SettingsBrowser **Expected behavior:** Codex should handle invalid or orphaned bookmark references gracefully without crashing or looping. **Actual behavior:** Endless error loop every ~3 seconds, OPDS becomes unusable for the client. **Error from logs:** django.db.utils.IntegrityError: FOREIGN KEY constraint failed ERROR | Updating bookmarks django.db.utils.IntegrityError: FOREIGN KEY constraint failed ERROR | Updating bookmarks [repeats indefinitely] **Workaround found:** Deleting the entire Codex config (database) and reinstalling Panels temporarily fixes the issue, but it reoccurs after a short time. **Environment:** Codex version: latest (Docker ghcr.io/ajslater/codex) OPDS client: Panels (iOS), multiple devices (iPhone + iPad) OPDS URL: /opds/v1.2/ Deployment: Docker on Synology NAS behind Nginx Proxy Manager