chore: import upstream snapshot with attribution

runtime/node/agent/providers/builtin_providers.py

@@ -0,0 +1,27 @@
+"""Register built-in agent providers."""
+
+from runtime.node.agent.providers.base import ProviderRegistry
+
+from runtime.node.agent.providers.openai_provider import OpenAIProvider
+
+ProviderRegistry.register(
+    "openai",
+    OpenAIProvider,
+    label="OpenAI",
+    summary="OpenAI models via the official OpenAI SDK (responses API)",
+)
+
+try:
+    from runtime.node.agent.providers.gemini_provider import GeminiProvider
+except ImportError:
+    GeminiProvider = None
+
+if GeminiProvider is not None:
+    ProviderRegistry.register(
+        "gemini",
+        GeminiProvider,
+        label="Google Gemini",
+        summary="Google Gemini models via google-genai",
+    )
+else:
+    print("Gemini provider not registered: google-genai library not found.")