fix(models): register gemma 4 model names

Author: pandego

src/google/adk/models/gemma_llm.py

@@ -205,7 +205,7 @@ def supported_models(cls) -> list[str]:
     """
 
     return [
-        r'gemma-3.*',
+        r'gemma-.*',
     ]
 
   @cached_property

tests/unittests/models/test_models.py

@@ -14,6 +14,7 @@
 
 from google.adk import models
 from google.adk.models.anthropic_llm import Claude
+from google.adk.models.gemma_llm import Gemma
 from google.adk.models.google_llm import Gemini
 from google.adk.models.lite_llm import LiteLlm
 import pytest
@@ -56,6 +57,19 @@ def test_match_claude_family(model_name):
   assert models.LLMRegistry.resolve(model_name) is Claude
 
 
+@pytest.mark.parametrize(
+    'model_name',
+    [
+        'gemma-3-27b-it',
+        'gemma-4-27b-it',
+        'gemma-4-31b-it',
+    ],
+)
+def test_match_gemma_family(model_name):
+  """Test that Gemma models are resolved correctly."""
+  assert models.LLMRegistry.resolve(model_name) is Gemma
+
+
 @pytest.mark.parametrize(
     'model_name',
     [