Add shard_00020.manifest.json

manifests/shard_00020.manifest.json

@@ -0,0 +1,15 @@
+{
+  "shard_id": 20,
+  "rows": 134252,
+  "size_mb": 211.49,
+  "compression": "zstd",
+  "source_breakdown": {
+    "fineweb_edu": 0.5536,
+    "cosmopedia_v2": 0.2781,
+    "tiny_strange": 0.0898,
+    "mini_en": 0.0486,
+    "tiny_textbooks": 0.0299
+  },
+  "created_at": "2026-06-27T09:24:05.239822Z",
+  "run_name": "bison-data-v2"
+}