feat(gather-v2): add Gather 2.0 recipe

[tavaresgmg]

Adds a separate gather-v2 recipe for Gather 2.0 (app.v2.gather.town), as agreed in ferdium/ferdium-app#2262. Gather 2.0 is a different platform from Classic — own domain, own auth, own offices — so the existing gather recipe (v1.1.1, app.gather.town/app) doesn't cover it.

No unread badge: the 2.0 UI is behind a paid workspace and I couldn't verify stable selectors for the chat counter, so webview.js only injects the service CSS. Happy to add badges in a follow-up if someone with a 2.0 office can share the markup.

Icon is the same Gather mark used by the existing recipe.

Ran pnpm i && pnpm lint:fix && pnpm reformat-files && pnpm package — 439 recipes packaged, 0 unsuccessful.

[stevenbressey]

Thanks a lot for creating the PR.
I just tested it quickly as I have an account with a 2.0 office, and I have exactly the same error as I had previously: the office loads correctly, but as soon as I start moving around the office, the service crashes with a grey window. No specific errors in the debug console a this moment. I suspect this is linked to some kind of WebGL/GPU/renderer issue, but not sure how to get the error log. I'm running Ferdium using Flatpak on Fedora 43.