ci: Add error handling for git pull failures

.forgejo/workflows/botserver.yaml

@@ -23,7 +23,10 @@ steps:
 - name: Setup
   run: |
     cd /opt/gbo/work/generalbots
-    git pull
+    if ! git pull; then
+      echo "::error::Git pull failed. Please resolve conflicts manually."
+      exit 1
+    fi
     git log --oneline -1
 
 - name: Build BotServer and BotUI