feat(engine): add support for MLX AI provider (#437)

* docs(CONTRIBUTING.md): update `TODO.md` reference (#435)

Signed-off-by: Emmanuel Ferdman <emmanuelferdman@gmail.com>

* feat(engine): add support for MLX AI provider
docs/engine: update documentation to include new engine providers

* fix(mlx.ts): add repetition_penalty option to generateCommitMessage method for improved model behavior

---------

Signed-off-by: Emmanuel Ferdman <emmanuelferdman@gmail.com>
Co-authored-by: Emmanuel Ferdman <emmanuelferdman@gmail.com>

src/engine/mlx.ts

@@ -0,0 +1,47 @@
+import axios, { AxiosInstance } from 'axios';
+import { OpenAI } from 'openai';
+import { AiEngine, AiEngineConfig } from './Engine';
+import { chown } from 'fs';
+
+interface MLXConfig extends AiEngineConfig {}
+
+export class MLXEngine implements AiEngine {
+    config: MLXConfig;
+    client: AxiosInstance;
+
+    constructor(config) {
+        this.config = config;
+        this.client = axios.create({
+            url: config.baseURL
+            ? `${config.baseURL}/${config.apiKey}`
+            : 'http://localhost:8080/v1/chat/completions',
+            headers: { 'Content-Type': 'application/json' }
+        });
+    }
+
+    async generateCommitMessage(
+        messages: Array<OpenAI.Chat.Completions.ChatCompletionMessageParam>): 
+        Promise<string | undefined> {
+            const params = {
+                messages,
+                temperature: 0, 
+                top_p: 0.1,
+                repetition_penalty: 1.5,
+                stream: false
+            };
+            try {
+                const response = await this.client.post(
+                    this.client.getUri(this.config),
+                    params
+                );
+                
+                const choices = response.data.choices;
+                const message = choices[0].message;
+                
+                return message?.content;
+            } catch (err: any) {
+                const message = err.response?.data?.error ?? err.message;
+                throw new Error(`MLX provider error: ${message}`);
+            }
+        }
+}