Add starcoder2: BigCode StarCoder2 family

scan.py

@@ -230,6 +230,13 @@ KNOWN_BASES = {
         "model_type_patterns": ["valley"],
         # Valley-Eagle-7B (151675) and Valley2.5 (151679) — close but distinct vocabs
     },
+    "starcoder2": {
+        "name": "BigCode StarCoder2",
+        "vocab_size": 49152,
+        "model_type_patterns": ["starcoder2"],
+        # 3B: hidden=3072/30L (97K dl), 7B: hidden=4608/32L, 15B: hidden=6144/40L
+        # Code-specialized tokenizer (49152 tokens)
+    },
     "zaya": {
         "name": "Zyphra ZAYA1 (deep hybrid SSM+Attention MoE)",
         "vocab_size": 262272,