feat(llm): añade factory que selecciona proveedor según settings

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

core/src/agentforge_core/llm/factory.py

@@ -0,0 +1,28 @@
+"""Factory que selecciona el LLMProvider según settings."""
+
+from __future__ import annotations
+
+from agentforge_core.config import Settings
+from agentforge_core.llm.azure import AzureOpenAIProvider
+from agentforge_core.llm.base import LLMProvider
+from agentforge_core.llm.mock import MockProvider
+from agentforge_core.llm.openai import OpenAIProvider
+
+
+def build_llm_provider(settings: Settings) -> LLMProvider:
+    """Materializa el proveedor activo. Falla en arranque si la config es inconsistente."""
+    match settings.llm_provider:
+        case "mock":
+            return MockProvider()
+        case "azure":
+            return AzureOpenAIProvider(
+                endpoint=settings.azure_openai_endpoint,
+                api_key=settings.azure_openai_api_key,
+                deployment=settings.azure_openai_deployment,
+                api_version=settings.azure_openai_api_version,
+            )
+        case "openai":
+            return OpenAIProvider(
+                api_key=settings.openai_api_key,
+                model=settings.openai_model,
+            )