feat(openai): add chat streaming and model commands

- add /openai (/chatgpt) chat command using OpenAI Responses API (streaming + incremental edits)
- add /openAIListModels, /openAIGetModel, /openAISetModel
- introduce base Command class and migrate non-chat commands to it
- wire OpenAI client + env vars (OPENAI_API_KEY, OPENAI_MODEL)
- bump deps (@google/genai, systeminformation, @types/node) and add openai

src/common/environment.ts

@@ -39,6 +39,9 @@ export class Environment {
     static MISTRAL_API_KEY?: string;
     static MISTRAL_MODEL: string;
 
+    static OPENAI_API_KEY?: string;
+    static OPENAI_MODEL: string;
+
     static waitText = "⏳ Дайте-ка подумать...";
     static analyzingPictureText = "🔍 Внимательно изучаю изображение...";
     static analyzingPicturesText = "🔍 Внимательно изучаю изображения...";
@@ -75,6 +78,9 @@ export class Environment {
 
         Environment.MISTRAL_API_KEY = process.env.MISTRAL_API_KEY;
         Environment.MISTRAL_MODEL = process.env.MISTRAL_MODEL || "mistral-small-latest";
+
+        Environment.OPENAI_API_KEY = process.env.OPENAI_API_KEY;
+        Environment.OPENAI_MODEL = process.env.OPENAI_MODEL || "gpt-4o-mini";
     }
 
     static setAdmins(admins: Set<number>) {
@@ -135,4 +141,8 @@ export class Environment {
     static setMistralModel(newModel: string) {
         Environment.MISTRAL_MODEL = newModel;
     }
+
+    static setOpenAIModel(newModel: string) {
+        Environment.OPENAI_MODEL = newModel;
+    }
 }