misc: simplified captcha flag and finalized build process

backend/src/lib/config/env.ts

@@ -122,8 +122,7 @@ const envSchema = z
     MAINTENANCE_MODE: zodStrBool.default("false"),
 
     // CAPTCHA
-    CAPTCHA_SECRET: zpStr(z.string().optional()),
-    CAPTCHA_ENABLED: zodStrBool.default("false")
+    CAPTCHA_SECRET: zpStr(z.string().optional())
   })
   .transform((data) => ({
     ...data,

backend/src/services/auth/auth-login-service.ts

@@ -204,7 +204,7 @@ export const authLoginServiceFactory = ({
     if (
       user.consecutiveFailedPasswordAttempts &&
       user.consecutiveFailedPasswordAttempts >= 10 &&
-      appCfg.CAPTCHA_ENABLED
+      Boolean(appCfg.CAPTCHA_SECRET)
     ) {
       if (!captchaToken) {
         throw new BadRequestError({