Refine S3 Tables implementation to address code review feedback

- Standardize namespace representation to []string
- Improve listing logic with pagination and StartFromFileName
- Enhance error handling with sentinel errors and robust checks
- Add JSON encoding error logging
- Fix CI workflow to use gofmt -l
- Standardize timestamps in directory creation
- Validate single-level namespaces

.github/workflows/s3-tables-tests.yml

@@ -133,10 +133,10 @@ jobs:
         run: |
           set -x
           echo "=== Checking S3 Tables Go format ==="
-          unformatted=$(go fmt ./weed/s3api/s3tables/... 2>&1 | wc -l)
-          if [ "$unformatted" -gt 0 ]; then
+          unformatted=$(gofmt -l ./weed/s3api/s3tables)
+          if [ -n "$unformatted" ]; then
             echo "Go format check failed - files need formatting"
-            go fmt ./weed/s3api/s3tables/...
+            echo "$unformatted"
             exit 1
           fi
           echo "All S3 Tables files are properly formatted"
@@ -145,10 +145,10 @@ jobs:
         run: |
           set -x
           echo "=== Checking S3 Tables test format ==="
-          unformatted=$(go fmt ./test/s3tables/... 2>&1 | wc -l)
-          if [ "$unformatted" -gt 0 ]; then
+          unformatted=$(gofmt -l ./test/s3tables)
+          if [ -n "$unformatted" ]; then
             echo "Go format check failed for tests"
-            go fmt ./test/s3tables/...
+            echo "$unformatted"
             exit 1
           fi
           echo "All S3 Tables test files are properly formatted"