Support GitHub Enterprise Server (custom hosts) in Forge

[bearylabs]

Currently selectForgeType() in src/forge/index.ts only matches github.com:

function selectForgeType(remoteUrl: string): GetForgeState | undefined { if (remoteUrl.includes('github.com')) {
    return getGithubForgeState; } return;
}

This means Forge (PRs/issues) silently does nothing for repos hosted on GitHub Enterprise Server / GHE.com domains (e.g.  mycompany.ghe.com ), even with  Forge-enabled  on.

Request: Add a setting, e.g.  magit.forgeCustomHosts , accepting a comma-separated list of additional GitHub hostnames.  selectForgeType  should also match these.  getGithubForgeState  would need to:

• derive owner/repo using the matched host instead of a hardcoded  github.com  string
• hit  https://<host>/api/graphql  instead of  https://api.github.com/graphql  for non-github.com hosts
• use GH CLI auth ( gh auth token ) for these hosts since  vscode.authentication 's built-in GitHub provider won't cover custom hosts

Happy to submit a PR for this if that approach sounds reasonable, let me know if you'd want it structured differently.