Support GitHub SSH host aliases for PR actions

Resolves the case where a remote like `git@github-work:owner/repo.git`
points at github.com via `~/.ssh/config` but Paseo treats it as
non-GitHub.

Adds a centralized GitHub remote resolver that parses standard remotes
directly and resolves SSH aliases via `ssh -G` (with hostname
validation to keep the alias out of ssh's option parser). The resolver
is shared by workspace GitHub feature detection, PR status, PR
creation, and workspace git metadata.

packages/server/src/utils/checkout-git.ts

@@ -11,7 +11,6 @@ import {
   GitHubCommandError,
   createGitHubService,
   resolveGitHubRepo,
-  type GitHubRepoRemoteUrlResolver,
   type GitHubService,
 } from "../services/github-service.js";
 import { parseGitRevParsePath, resolveGitRevParsePath } from "./git-rev-parse-path.js";
@@ -2277,11 +2276,10 @@ export async function createPullRequest(
   cwd: string,
   options: CreatePullRequestOptions,
   github: GitHubService = createGitHubService(),
-  workspaceGitService: GitHubRepoRemoteUrlResolver,
   context?: CheckoutContext,
 ): Promise<{ url: string; number: number }> {
   await requireGitRepo(cwd);
-  const repo = await resolveGitHubRepo(cwd, { workspaceGitService });
+  const repo = await resolveGitHubRepo(cwd);
   if (!repo) {
     throw new Error("Unable to determine GitHub repo from git remote");
   }