Effect tracks entire store instead of properties used

[knd775]

Describe the bug

If a property of a store is used in an effect, the entire store becomes a dependency.

This is especially an issue when using something like superforms that stores formdata in a single store. Changing one field will cause all effects referencing any field to run.

Reproduction

https://svelte.dev/playground/ca42f41442a549d1a37ec9c4073cb061?version=5.1.4

Logs

No response

System Info

System:
  OS: Linux 5.15 Ubuntu 22.04.5 LTS 22.04.5 LTS (Jammy Jellyfish)
  CPU: (12) x64 12th Gen Intel(R) Core(TM) i5-12400F
  Memory: 8.01 GB / 15.54 GB
  Container: Yes
  Shell: 5.8.1 - /usr/bin/zsh
Binaries:
  Node: 20.18.0 - ~/.nvm/versions/node/v20.18.0/bin/node
  Yarn: 1.22.22 - /mnt/c/Users/bayles/AppData/Local/pnpm/yarn
  npm: 10.8.2 - ~/.nvm/versions/node/v20.18.0/bin/npm
  pnpm: 9.12.3 - /mnt/c/Users/bayles/AppData/Local/pnpm/pnpm
npmPackages:
  svelte: ^5.1.4 => 5.1.2

Severity

blocking an upgrade

[Conduitry]

I believe this is a limitation of how stores work. They report updates about their whole value - not in a fine-grained way. This would be good to document, though.

Depending on what you're doing, $derived() might be one way to deal with this. https://svelte.dev/playground/hello-world?version=5.1.4#H4sIAAAAAAAACo2R3WqEMBCFX2UIgsou2mtXhd71HWopiY4lNCYSx90Wybs3_nVLu7C9CeTMd84MMxPTvEOWsSdUysDFWNVAhI0kbGJ2ZK1UOLDseWL02c_cLHh9cz32fTKcUdGsCT7gLb02mlCTj2H5UFvZU1npimTXG0swwcVK4kIhOGit6SBcnelAxmJ4mlkfMRAsAhTfhmgCnsHDEYR_wcULqnADX7lHgwatPGMTBYuW8N-QuAGJFQqwbbGmKIqhKGGapYq26NP6m-cyChNl3qJw7Bvu1wZ7q3CNcXfTxD_SxM-0PL3uUediJDIajK6VrN-Lae2wT3E4uHIpAM_TFfXt96q75xdXv_jrF87fl_CDWEZ2RPfivgBr95YYUQIAAA==