Add Ollama support for local LLM models (Phase 2 complete)

Major Changes:
- Added Ollama as alternative LLM provider to OpenAI
- Implemented flexible provider switching via environment variables
- Support for multiple embedding models (OpenAI and Ollama)
- Created comprehensive Ollama setup guide

Configuration Changes (config.py):
- Added LLM_PROVIDER and EMBEDDER_PROVIDER settings
- Added Ollama configuration: base URL, LLM model, embedding model
- Modified get_mem0_config() to dynamically switch providers
- OpenAI API key now optional when using Ollama
- Added validation to ensure required keys based on provider

Supported Configurations:
1. Full OpenAI (default):
   - LLM_PROVIDER=openai
   - EMBEDDER_PROVIDER=openai

2. Full Ollama (local):
   - LLM_PROVIDER=ollama
   - EMBEDDER_PROVIDER=ollama

3. Hybrid configurations:
   - Ollama LLM + OpenAI embeddings
   - OpenAI LLM + Ollama embeddings

Ollama Models Supported:
- LLM: llama3.1:8b, llama3.1:70b, mistral:7b, codellama:7b, phi3:3.8b
- Embeddings: nomic-embed-text, mxbai-embed-large, all-minilm

Documentation:
- Created docs/setup/ollama.mdx - Complete Ollama setup guide
  - Installation methods (host and Docker)
  - Model selection and comparison
  - Docker Compose configuration
  - Performance tuning and GPU acceleration
  - Migration guide from OpenAI
  - Troubleshooting section
- Updated README.md with Ollama features
- Updated .env.example with provider selection
- Marked Phase 2 as complete in roadmap

Environment Variables:
- LLM_PROVIDER: Select LLM provider (openai/ollama)
- EMBEDDER_PROVIDER: Select embedding provider (openai/ollama)
- OLLAMA_BASE_URL: Ollama API endpoint (default: http://localhost:11434)
- OLLAMA_LLM_MODEL: Ollama model for text generation
- OLLAMA_EMBEDDING_MODEL: Ollama model for embeddings
- MEM0_EMBEDDING_DIMS: Must match embedding model dimensions

Breaking Changes:
- None - defaults to OpenAI for backward compatibility

Migration Notes:
- When switching from OpenAI to Ollama embeddings, existing embeddings
  must be cleared due to dimension changes (1536 → 768 for nomic-embed-text)
- Update MEM0_EMBEDDING_DIMS to match chosen embedding model

Benefits:
✅ Cost savings - no API costs with local models
✅ Privacy - all data stays local
✅ Offline capability - works without internet
✅ Model variety - access to many open-source models
✅ Flexibility - easy switching between providers

Version: 1.1.0
Status: Phase 2 Complete - Production Ready with Ollama Support

🤖 Generated with Claude Code

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

config.py

@@ -12,8 +12,17 @@ from pydantic import Field
 class Settings(BaseSettings):
     """Application settings loaded from environment variables"""
 
+    # LLM Provider Selection
+    llm_provider: str = Field(default="openai", env="LLM_PROVIDER")  # openai or ollama
+    embedder_provider: str = Field(default="openai", env="EMBEDDER_PROVIDER")  # openai or ollama
+
     # OpenAI
-    openai_api_key: str = Field(..., env="OPENAI_API_KEY")
+    openai_api_key: str = Field(default="", env="OPENAI_API_KEY")  # Optional if using Ollama
+
+    # Ollama
+    ollama_base_url: str = Field(default="http://localhost:11434", env="OLLAMA_BASE_URL")
+    ollama_llm_model: str = Field(default="llama3.1:8b", env="OLLAMA_LLM_MODEL")
+    ollama_embedding_model: str = Field(default="nomic-embed-text", env="OLLAMA_EMBEDDING_MODEL")
 
     # Supabase
     supabase_connection_string: str = Field(..., env="SUPABASE_CONNECTION_STRING")
@@ -60,7 +69,7 @@ def get_settings() -> Settings:
 
 def get_mem0_config(settings: Settings) -> Dict[str, Any]:
     """
-    Generate Mem0 configuration from settings
+    Generate Mem0 configuration from settings with support for OpenAI and Ollama
 
     Args:
         settings: Application settings
@@ -68,6 +77,51 @@ def get_mem0_config(settings: Settings) -> Dict[str, Any]:
     Returns:
         Dict containing Mem0 configuration
     """
+    # LLM Configuration - Switch between OpenAI and Ollama
+    if settings.llm_provider.lower() == "ollama":
+        llm_config = {
+            "provider": "ollama",
+            "config": {
+                "model": settings.ollama_llm_model,
+                "temperature": 0.1,
+                "max_tokens": 2000,
+                "ollama_base_url": settings.ollama_base_url
+            }
+        }
+    else:  # Default to OpenAI
+        if not settings.openai_api_key:
+            raise ValueError("OPENAI_API_KEY is required when LLM_PROVIDER=openai")
+        llm_config = {
+            "provider": "openai",
+            "config": {
+                "model": "gpt-4o-mini",
+                "temperature": 0.1,
+                "max_tokens": 2000,
+                "api_key": settings.openai_api_key
+            }
+        }
+
+    # Embedder Configuration - Switch between OpenAI and Ollama
+    if settings.embedder_provider.lower() == "ollama":
+        embedder_config = {
+            "provider": "ollama",
+            "config": {
+                "model": settings.ollama_embedding_model,
+                "ollama_base_url": settings.ollama_base_url
+            }
+        }
+    else:  # Default to OpenAI
+        if not settings.openai_api_key:
+            raise ValueError("OPENAI_API_KEY is required when EMBEDDER_PROVIDER=openai")
+        embedder_config = {
+            "provider": "openai",
+            "config": {
+                "model": "text-embedding-3-small",
+                "embedding_dims": settings.mem0_embedding_dims,
+                "api_key": settings.openai_api_key
+            }
+        }
+
     return {
         # Vector Store - Supabase
         "vector_store": {
@@ -91,26 +145,11 @@ def get_mem0_config(settings: Settings) -> Dict[str, Any]:
             }
         },
 
-        # LLM Provider - OpenAI
-        "llm": {
-            "provider": "openai",
-            "config": {
-                "model": "gpt-4o-mini",
-                "temperature": 0.1,
-                "max_tokens": 2000,
-                "api_key": settings.openai_api_key
-            }
-        },
+        # LLM Provider - Dynamic (OpenAI or Ollama)
+        "llm": llm_config,
 
-        # Embedder - OpenAI
-        "embedder": {
-            "provider": "openai",
-            "config": {
-                "model": "text-embedding-3-small",
-                "embedding_dims": settings.mem0_embedding_dims,
-                "api_key": settings.openai_api_key
-            }
-        },
+        # Embedder - Dynamic (OpenAI or Ollama)
+        "embedder": embedder_config,
 
         # Version
         "version": settings.mem0_version