Add MiniMax LLM integration and local .env support

- Add .env to .gitignore (API keys stay local)
- Add LLM client with MiniMax and OpenAI support
- Update config to load from environment variables
- Wire up Architect agent to actually call the LLM
- Add MiniMax API key to local .env file

opus_orchestrator/agents/base.py

@@ -1,11 +1,12 @@
 """Base agent class for Opus Orchestrator."""
 
 from abc import ABC, abstractmethod
-from typing import Any, Generic, TypeVar
+from typing import Any, Generic, Optional, TypeVar
 
 from pydantic import BaseModel
 
 from opus_orchestrator.config import AgentConfig, get_config
+from opus_orchestrator.utils.llm import LLMClient, get_llm_client
 
 
 T = TypeVar("T", bound=BaseModel)
@@ -23,9 +24,6 @@ class AgentResponse(BaseModel):
         arbitrary_types_allowed = True
 
 
-from typing import Optional
-
-
 class BaseAgent(ABC, Generic[T]):
     """Base class for all Opus agents.
 
@@ -49,6 +47,14 @@ class BaseAgent(ABC, Generic[T]):
         self.system_prompt = system_prompt
         self.output_schema = output_schema
         self.config = config or get_config().agent
+        self._llm_client: Optional[LLMClient] = None
+
+    @property
+    def llm_client(self) -> LLMClient:
+        """Get or create LLM client."""
+        if self._llm_client is None:
+            self._llm_client = get_llm_client()
+        return self._llm_client
 
     @abstractmethod
     async def execute(self, input_data: Any, context: dict[str, Any]) -> AgentResponse:
@@ -63,6 +69,31 @@ class BaseAgent(ABC, Generic[T]):
         """
         pass
 
+    async def call_llm(
+        self,
+        system_prompt: str,
+        user_prompt: str,
+        temperature: Optional[float] = None,
+    ) -> str:
+        """Call the LLM with prompts.
+        
+        Args:
+            system_prompt: System prompt
+            user_prompt: User prompt
+            temperature: Optional temperature override
+            
+        Returns:
+            Generated text
+        """
+        temp = temperature if temperature is not None else self.config.temperature
+        
+        return await self.llm_client.complete(
+            system_prompt=system_prompt,
+            user_prompt=user_prompt,
+            temperature=temp,
+            max_tokens=self.config.max_tokens,
+        )
+
     def build_system_prompt(self, context: dict[str, Any]) -> str:
         """Build the full system prompt with context.
 
@@ -104,3 +135,9 @@ class BaseAgent(ABC, Generic[T]):
 
 Please complete this task following the methodology specified in your system prompt.
 """
+
+    async def cleanup(self):
+        """Clean up resources."""
+        if self._llm_client:
+            await self._llm_client.close()
+            self._llm_client = None