feat(ai): add configurable default provider + refactor telegram handlers

- add AiProvider enum and DEFAULT_AI_PROVIDER env var (fallback: OLLAMA)
- route chat execution based on selected provider (Ollama/Gemini/Mistral/OpenAI)
- move inline query / callback / edited message / my_chat_member handlers into utils
- minor cleanup (command requirements placement, whitespace)

src/common/environment.ts

@@ -3,6 +3,13 @@ import {saveData} from "../db/database";
 import {Answers} from "../model/answers";
 import {ifTrue} from "../util/utils";
 
+export enum AiProvider {
+    OLLAMA = "OLLAMA",
+    GEMINI = "GEMINI",
+    MISTRAL = "MISTRAL",
+    OPENAI = "OPENAI",
+}
+
 export class Environment {
     static BOT_TOKEN: string;
     static TEST_ENVIRONMENT: boolean;
@@ -24,6 +31,8 @@ export class Environment {
 
     static MAX_PHOTO_SIZE: number;
 
+    static DEFAULT_AI_PROVIDER: AiProvider;
+
     static SYSTEM_PROMPT?: string;
 
     static OLLAMA_ADDRESS?: string;
@@ -65,6 +74,13 @@ export class Environment {
 
         Environment.MAX_PHOTO_SIZE = Number(process.env.MAX_PHOTO_SIZE || "1280");
 
+        const aiProvider = process.env.DEFAULT_AI_PROVIDER || "OLLAMA";
+        if (Object.values(AiProvider).includes(aiProvider as AiProvider)) {
+            Environment.DEFAULT_AI_PROVIDER = aiProvider as AiProvider;
+        } else {
+            Environment.DEFAULT_AI_PROVIDER = AiProvider.OLLAMA;
+        }
+
         Environment.SYSTEM_PROMPT = process.env.SYSTEM_PROMPT?.trim();
 
         Environment.OLLAMA_ADDRESS = process.env.OLLAMA_ADDRESS;