fix: resolve CI linting and type errors

src/promptforge/providers/__init__.py

@@ -1,6 +1,16 @@
+"""LLM Provider abstraction layer."""
+
+from .base import ProviderBase, ProviderResponse
 from .factory import ProviderFactory
 from .openai import OpenAIProvider
 from .anthropic import AnthropicProvider
 from .ollama import OllamaProvider
 
-__all__ = ["ProviderFactory", "OpenAIProvider", "AnthropicProvider", "OllamaProvider"]
+__all__ = [
+    "ProviderBase",
+    "ProviderResponse",
+    "ProviderFactory",
+    "OpenAIProvider",
+    "AnthropicProvider",
+    "OllamaProvider",
+]