fix: remove continue-on-error from checkout, increase timeout to 5min

The continue-on-error flag causes the checkout step to always show a
red cross in Gitea UI even on success. Removed it since the rsync
fallback is now conditional and ~/archy is up to date. Increased
timeout from 3 to 5 minutes for slow LAN fetches.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/build-iso-dev.yml

@@ -15,8 +15,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           fetch-depth: 1
-        timeout-minutes: 3
-        continue-on-error: true
+        timeout-minutes: 5
 
       - name: Sync from local repo (fallback if checkout failed)
         run: |