custom.css, config.edn, etc. do not function when they belong to read-only filesystems

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### Search first

- [X] I searched and no similar issues were found

### What Happened?

When the `custom.css` file (located at `/logseqdirectory/graphdirectory/logseq/custom.css`) is a symbolic link to a file in a read-only filesystem, the contents will appear in the in-app 'edit custom.css' page, but will not have any effect. The same seems to be the case with the `config.edn` file within the same directory.

### Reproduce the Bug

1. Create a custom.css file in a read only filesystem, then create a symbolic link in `/logseqdirectory/graphdirectory/logseq/custom.css`
1a. In my case this means declaring the `custom.css` file with home-manager.
2. Launch the logseq application. Enter `Settings > Edit custom.css`
3. The text of your linked file should be visible, since it is named correctly and in the right place, but the CSS will never update.

### Expected Behavior

`custom.css` declared using home-manager, or any otherwise valid `.css` file that is linked from a RO directory, should be read and applied properly by logseq.

### Desktop or Mobile Platform Information

NixOS `24.05`
Using nixpkgs unstable, home-manager, and nix-flakes
Logseq version `0.10.8`

### Additional Context

I have found a workaround for this issue, which involves declaring the `custom.css` and `config.edn` in a nearby directory, then setting home-manager's `home.file."filename".onChange` setting to a script that copies the file from the directory it's created in to the `/logseq` directory of my graph.

### Are you willing to submit a PR? If you know how to fix the bug.

- [ ] I'm willing to submit a PR (Thank you!)

Start by tracing how the Logseq application loads `logseq/custom.css` and `logseq/config.edn`, especially when those paths are symbolic links into a read-only filesystem. Reproduce the NixOS 24.05 setup and verify that linked `custom.css` is applied and linked `config.edn` is honored without copying either file.

Written by the indexing model from the issue text.