s3tables: accept .puffin deletion vectors in table data/ (#11844)

* s3tables: accept .puffin data files for Iceberg v3 deletion vectors

Iceberg v3 writes deletion vectors as Puffin files under a table's data/
directory, so merge-on-read DELETE and UPDATE on v3 tables were refused
with AccessDenied by the table-bucket upload validator.

Fixes #11842

* s3tables: name all accepted data formats in rejection error

The message stopped at .avro even though .lance and now .puffin are
accepted.

* s3tables: cover deletion-vector filenames in data layout test

Uses the names real engines emit: Spark/Iceberg Java
{seq}-{task}-{uuid}-{counter}-deletes.puffin, UUID-suffixed names, and
the same under a partition directory.

weed/s3api/s3tables/iceberg_layout.go

@@ -15,7 +15,7 @@ import (
 // - metadata/v*.metadata.json (table metadata)
 // - metadata/snap-*.avro (snapshot manifest lists)
 // - metadata/*.avro (manifest files)
-// - data/*.parquet, data/*.orc, data/*.avro (data files)
+// - data/*.parquet, *.orc, *.avro, *.puffin (data files)
 
 const uuidPattern = `[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}`
 
@@ -75,6 +75,7 @@ var (
 		regexp.MustCompile(`^[^/]+\.parquet$`), // Parquet files
 		regexp.MustCompile(`^[^/]+\.orc$`),     // ORC files
 		regexp.MustCompile(`^[^/]+\.avro$`),    // Avro files
+		regexp.MustCompile(`^[^/]+\.puffin$`),  // Iceberg v3 deletion vectors
 		regexp.MustCompile(`^[^/]+\.lance$`),   // Lance fragments
 	}
 
@@ -209,7 +210,7 @@ func validateFilePatterns(filename string, isMetadata bool) error {
 		errorMsg = "invalid metadata file format: must be a valid Iceberg metadata, manifest, or snapshot file"
 	} else {
 		patterns = dataFilePatterns
-		errorMsg = "invalid data file format: must be .parquet, .orc, or .avro"
+		errorMsg = "invalid data file format: must be .parquet, .orc, .avro, .puffin or .lance"
 	}
 
 	for _, pattern := range patterns {

weed/s3api/s3tables/iceberg_layout_test.go

@@ -90,6 +90,9 @@ func TestIcebergLayoutValidator_AcceptsRealWorldDataFiles(t *testing.T) {
 		"data/part-00000.parquet",
 		"data/some-file.orc",
 		"data/year=2026/month=05/00000-0-uuid.parquet",
+		"data/00000-2-c56b1e21-828c-40ad-8f7b-739c6cb82dcf-00001-deletes.puffin",
+		"data/82e3eec4-3aee-414f-a444-94c03c641d20-deletes.puffin",
+		"data/year=2026/month=05/00000-2-c56b1e21-828c-40ad-8f7b-739c6cb82dcf-00001-deletes.puffin",
 	}
 	v := NewIcebergLayoutValidator()
 	for _, p := range cases {