add gemini and mistral models to environment

src/commands/gemini-chat.ts

@@ -68,7 +68,7 @@ export class GeminiChat extends ChatCommand {
             });
 
             const stream = await this.googleAi.models.generateContentStream({
-                model: "gemini-2.5-flash",
+                model: Environment.GEMINI_MODEL || "gemini-2.5-flash",
                 contents: chatContent,
             });
 

src/commands/mistral-chat.ts

@@ -103,7 +103,7 @@ export class MistralChat extends ChatCommand {
             });
 
             const stream = await this.mistralAi.chat.stream({
-                model: "mistral-small-latest",
+                model: Environment.MISTRAL_MODEL || "mistral-small-latest",
                 messages: chatMessages as any
             });