[BUG] Export creates a .txt & Import expects a .json

[jameswragg]

Describe the bug
I export my config from Chrome into my Downloads dir & it creates a HE_2025-02-03T13-29-20Z.txt file. I go to Import that config from Firefox & it doesn't let me choose the file to import as the file picker is limited to only *.json files.

Extra informations
I'm using macOS 14.6.1

[wesinator]

That's weird because the export name is returned as a json -

HeaderEditor/src/pages/options/utils.ts

Line 6 in ec1cf31

return `HE_${date}${additional ? '_' + additional : ''}.json`;

I think this is a macOS thing where it assigns a .txt extension to text files if there isn't a mimetype specified.
The export calls file.save which appears to only be used for json, but does not specify a mime/content type:

HeaderEditor/src/share/pages/file.ts

Line 4 in ec1cf31

const fileUrl = URL.createObjectURL(blob);