docs: new algorithm migration guides + memory evaluation (#4811)

Co-authored-by: kartik-mem0 <kartik.labhshetwar@mem0.ai>
Co-authored-by: Saket Aryan <saketaryan2002@gmail.com>

docs/components/llms/models/langchain.mdx

@@ -21,7 +21,7 @@ os.environ["OPENAI_API_KEY"] = "your-api-key"
 
 # Initialize a LangChain model directly
 openai_model = ChatOpenAI(
-    model="gpt-4.1-nano-2025-04-14",
+    model="gpt-5-mini",
     temperature=0.2,
     max_tokens=2000
 )

docs/components/llms/models/litellm.mdx

@@ -16,7 +16,7 @@ config = {
     "llm": {
         "provider": "litellm",
         "config": {
-            "model": "gpt-4.1-nano-2025-04-14",
+            "model": "gpt-5-mini",
             "temperature": 0.2,
             "max_tokens": 2000,
         }

docs/components/llms/models/openai.mdx

@@ -20,7 +20,7 @@ config = {
     "llm": {
         "provider": "openai",
         "config": {
-            "model": "gpt-4.1-nano-2025-04-14",
+            "model": "gpt-5-mini",
             "temperature": 0.2,
             "max_tokens": 2000,
         }
@@ -86,7 +86,7 @@ config = {
     "llm": {
         "provider": "openai_structured",
         "config": {
-            "model": "gpt-4.1-nano-2025-04-14",
+            "model": "gpt-5-mini",
             "temperature": 0.0,
         }
     }