feat: add MiniMax as LLM text completion provider

- Add MiniMax chat model provider using OpenAI-compatible API
- Support MiniMax-M2.7 and MiniMax-M2.7-highspeed models
- Temperature clamping to MiniMax valid range (0.0, 1.0]
- Streaming support with token usage tracking
- MINIMAX_API_KEY environment variable support
- Add text-completion-minimax entry point
- Add 15 unit tests and 3 integration tests
- Update README with MiniMax in LLM APIs list

tests/integration/test_minimax_integration.py

@@ -0,0 +1,86 @@
+"""
+Integration tests for MiniMax text completion provider.
+Tests actual API calls to MiniMax when MINIMAX_API_KEY is available.
+"""
+
+import os
+import pytest
+from openai import OpenAI
+
+MINIMAX_API_KEY = os.getenv("MINIMAX_API_KEY")
+MINIMAX_BASE_URL = "https://api.minimax.io/v1"
+
+
+@pytest.mark.skipif(
+    not MINIMAX_API_KEY,
+    reason="MINIMAX_API_KEY not set"
+)
+class TestMiniMaxIntegration:
+    """Integration tests that call the real MiniMax API"""
+
+    def get_client(self):
+        return OpenAI(api_key=MINIMAX_API_KEY, base_url=MINIMAX_BASE_URL)
+
+    def test_basic_chat_completion(self):
+        """Test basic chat completion with MiniMax-M2.7"""
+        client = self.get_client()
+
+        resp = client.chat.completions.create(
+            model="MiniMax-M2.7",
+            messages=[{
+                "role": "user",
+                "content": 'Say "test passed" and nothing else.'
+            }],
+            temperature=1.0,
+            max_tokens=64,
+        )
+
+        assert resp.choices[0].message.content is not None
+        assert len(resp.choices[0].message.content) > 0
+        assert resp.usage.prompt_tokens > 0
+        assert resp.usage.completion_tokens > 0
+
+    def test_highspeed_model(self):
+        """Test chat completion with MiniMax-M2.7-highspeed"""
+        client = self.get_client()
+
+        resp = client.chat.completions.create(
+            model="MiniMax-M2.7-highspeed",
+            messages=[{
+                "role": "user",
+                "content": 'Say "highspeed test passed" and nothing else.'
+            }],
+            temperature=1.0,
+            max_tokens=64,
+        )
+
+        assert resp.choices[0].message.content is not None
+        assert len(resp.choices[0].message.content) > 0
+
+    def test_streaming_completion(self):
+        """Test streaming chat completion"""
+        client = self.get_client()
+
+        response = client.chat.completions.create(
+            model="MiniMax-M2.7",
+            messages=[{
+                "role": "user",
+                "content": 'Say "stream test passed" and nothing else.'
+            }],
+            temperature=1.0,
+            max_tokens=64,
+            stream=True,
+            stream_options={"include_usage": True}
+        )
+
+        chunks = list(response)
+        assert len(chunks) > 0
+
+        # Collect text from chunks
+        texts = []
+        for chunk in chunks:
+            if chunk.choices and chunk.choices[0].delta.content:
+                texts.append(chunk.choices[0].delta.content)
+
+        full_text = "".join(texts)
+        assert len(full_text) > 0