Add Modrinth desktop app

anda/games/modrinth/anda.hcl

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+project pkg {
+    rpm {
+        spec = "modrinth.spec"
+    }
+}

anda/games/modrinth/modrinth.spec

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+Name:           modrinth
+Version:        1.2.3
+Release:        1%?dist
+Summary:        Desktop app for managing mods and modpacks from Modrinth
+URL:            https://github.com/modrinth/code
+License:        GPL-3.0-or-later
+BuildRequires:  git-core rust tauri
+Packager:       Willow Reed <willow@willowidk.dev>
+ 
+%description
+Desktop app for managing mods and modpacks from Modrinth
+ 
+%prep
+rm -rf ./*
+git clone --recursive %{url} .
+git checkout v%{version}
+ 
+%build
+# Vendor PNPM directly instead of installing from packages, because we need to somehow force PNPM to use Node.js 20
+# We are not using Fedora's PNPM because we need to use `pnpm env`, which PNPM does not support when not vendored directly from upstream
+curl -fsSL https://get.pnpm.io/install.sh | sh -
+source /builddir/.bashrc
+pnpm env use --global 20
+pnpm install
+pnpm build
+pnpm electron-builder --linux --dir
+ 
+%install
+echo "this will also run when building pkg but for installing it into %{buildroot} so that anda (mock) can package it"
+ 
+%files
+/usr/bin/pkgname-binary
+/path/to/more/files/*/package
+ 
+%changelog
+* Wed Jan 11 2006 your-username-here <your_email@idk.xyz>
+- Description on what you've done

anda/games/modrinth/update.rhai

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+rpm.version(find(`https://launcher-files.modrinth.com/versions/([/d/.]+)/linux/Modrinth%20App_.+?_amd64.AppImage`, get("https://modrinth.com/app"), 1));