Publish v2.6.0 to extension stores and set up maintainer publishing access

[PeterDaveHello]

I released v2.6.0 on GitHub, but the README-linked extension stores have not
been updated yet. Chrome Web Store, Microsoft Edge Add-ons, and Firefox AMO are
still serving 2.5.9. Safari App Store status is unclear and may no longer be
applicable.

The store listings appear to still be under @josStorer's publisher accounts, so
I currently cannot publish the store updates myself.

Could you help publish v2.6.0 to the applicable stores first?

For longer-term maintenance, there are official team/access mechanisms we can
use or verify:

• Chrome Web Store supports publisher members and roles:
  https://developer.chrome.com/docs/webstore/share-ownership
• Firefox AMO supports add-on owners/authors and ownership transfer:
  https://extensionworkshop.com/documentation/publish/add-on-ownership/
• Microsoft Edge Add-ons supports multi-user Edge program accounts through
  Partner Center / Microsoft Entra, but the exact access model should be checked
  in Partner Center:
  https://learn.microsoft.com/en-us/microsoft-edge/extensions/publish/create-dev-account
• App Store Connect supports users/roles and app transfer, if Safari remains
  applicable:
  https://developer.apple.com/help/app-store-connect/manage-your-team/overview-of-accounts-and-roles/
  https://developer.apple.com/help/app-store-connect/transfer-an-app/overview-of-app-transfer/

Once maintainer access is set up, we can add automated store publishing to the
GitHub Actions release workflow.

[josStorer]

Received. I think I can recently add support for automated submissions to the store in the workflow.

[josStorer]

Regarding the App Store, I believe I can no longer support it, as Apple has consistently prevented the app from being listed, and I have had prolonged communication with support without any results.