Tamagotchi app gets stuck on loading screen when localStorage references a deleted custom stage model

[NashChennc]

Describe the bug

the tamagotchi app getting stuck on the loading screen when localStorage points to a custom stage model that no longer exists in IndexedDB

The renderer could become disabled when settings/stage/model referenced a stale custom model id. Since no valid stage renderer was mounted, the app stayed on the loading screen.

System Info

System:
    OS: macOS 26.4.1
    CPU: (10) arm64 Apple M4
    Memory: 1.61 GB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 24.16.0 - ~/.local/state/fnm_multishells/98399_1781621357489/bin/node
    npm: 11.13.0 - ~/.local/state/fnm_multishells/98399_1781621357489/bin/npm
    pnpm: 10.33.0 - ~/.local/state/fnm_multishells/98399_1781621357489/bin/pnpm
  Browsers:
    Chrome: 149.0.7827.103
    Safari: 26.4

Validations

• Follow our Code of Conduct
• Read the Contributing Guide.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A, please open a GitHub Discussion instead.

Contributions

• I am willing to submit a PR to fix this issue
• I am willing to submit a PR with failing tests (actually just go ahead and do it, thanks!)

[NashChennc]

#1914 attempts to fix this issue, but more investigation is needed to determine the right solution.

The PR is currently a draft.