BetterDiscord won't load despite successful install

**Describe the bug**
BetterDiscord installer runs successfully, but when Discord is relaunched the client behaves identical to vanilla - the BD loading icon does not appear, plugins do not load, and the BD menus do not appear. I have tried reinstalling, uninstalling and repairing the BD install multiple times.

**To Reproduce**
Steps to reproduce the behaviour:
1. Run BetterDiscord installer and select 'install'
2. Select '.../discord/app-0.0.399/modules/discord_desktop_core-1/discord_desktop_core'
3. Allow the installer to run, report success and restart Discord
4. Discord restarts, BD does not load

**Expected behaviour**
For BD to load...

**Screenshots**

**System Information:**
- OS: Mac OS X Sequoia 15.7.7
- Discord Version: Stable 580156 (af60699)

**Additional context**
Seems to have started about ~2 days ago after my Discord client updated - I'm aware BD will typically be removed after an update, but it will usually work again after running the installer.

Start by reproducing the installer flow on Mac OS X Sequoia 15.7.7 with Discord Stable 580156, selecting the reported discord_desktop_core path and checking whether the install reports success. Compare the resulting Discord launch with the expected BD loading icon, plugins, and menus; done means BetterDiscord loads after installation.

Written by the indexing model from the issue text.