Add rule change alerts on extension updates.

[aiktb]

Is your feature request related to a problem? Please describe.

For example, when twitter.com migrates to x.com, what should be done to update the old rules and prevent conflicts?

Describe the solution you'd like

One possible solution is to add a dialog to options.html that lets users choose whether they want to import new rules or delete outdated ones, etc.
The callback to open the options page and pop up the dialog should be registered in the event listener that the extension update.

Describe alternatives you've considered

No response

Additional context

Important

If the user updates more than one version at a time, the changes from these versions should be merged and shown to the user.

Validations

• Check if you're on the latest Furigana Maker version.
• Follow our Code of Conduct
• Check that there isn't already an issue that asks for the same feature to avoid creating a duplicate.
• I would like to implement this feature via a PR.

[aiktb]

No longer necessary, wxt/stroage provides a good mechanism to migrate storage versions, it's simple.
And with auto-detection complete, updating the rules list in real time is no longer important.