fix(ci): resolve YAML syntax error in Forgejo workflow

- Replace heredoc with pipe to avoid YAML parsing errors
- Fixes 'could not find expected ':' error on line 75

.forgejo/workflows/build.yaml

@@ -48,7 +48,7 @@ jobs:
           fi
 
           : > /tmp/changed-services.txt
-          while IFS= read -r f; do
+          echo "$CHANGED_FILES" | while IFS= read -r f; do
             case "$f" in
               apps/gateway/*) echo gateway >> /tmp/changed-services.txt ;;
               apps/users/*) echo users >> /tmp/changed-services.txt ;;
@@ -71,9 +71,7 @@ jobs:
               apps/ugc_content_creators/*) echo ugc-content-creators >> /tmp/changed-services.txt ;;
               apps/cron/*) echo cron >> /tmp/changed-services.txt ;;
             esac
-          done <<EOF2
-$CHANGED_FILES
-EOF2
+          done
 
           sort -u /tmp/changed-services.txt -o /tmp/changed-services.txt