ci(upstream-sync): fetch from GitHub directly, skip the mirror layer

The Gitea pull-mirror of element-hq/element-x-android is slow to
populate its initial clone (~12 GB). Rather than block workflow
verification on the mirror landing, fetch straight from GitHub — the
runner has outbound access and GitHub isn't flaky. The mirror stays in
place as a fallback / LAN-cache for humans doing manual git fetches.

.gitea/workflows/upstream-sync.yml

@@ -27,14 +27,15 @@ jobs:
           # Built-in token Gitea hands us — scoped to this repo, has push.
           token: ${{ secrets.GITEA_TOKEN }}
 
-      - name: Wire upstream mirror + fetch wallet
+      - name: Fetch upstream + wallet
         run: |
           set -euo pipefail
-          # Sulkta-Coop/element-x-upstream is a read-only pull-mirror of
-          # github.com/element-hq/element-x-android. Kept local for
-          # LAN-speed fetches and offline resilience.
-          git remote add upstream http://192.168.0.5:3001/Sulkta-Coop/element-x-upstream.git
-          git fetch upstream develop
+          # Fetch directly from GitHub. We also have a Gitea pull-mirror
+          # at Sulkta-Coop/element-x-upstream that tracks this same repo,
+          # but sourcing from GitHub keeps the workflow independent of
+          # the mirror's health — one less moving part to diagnose.
+          git remote add upstream https://github.com/element-hq/element-x-android.git
+          git fetch --depth=500 upstream develop
           git fetch origin wallet:refs/remotes/origin/wallet
 
       - name: Fast-forward main