refactor: replace ignored numeric literals with constants

src/config/env.validation.ts

@@ -1,3 +1,6 @@
+const MIN_PORT = 1;
+const MIN_REQUESTS_PER_SECOND = 1;
+
 const DEFAULT_PORT = 3000;
 const DEFAULT_TBANK_RATE_LIMIT_PER_SECOND = 5;
 const MAX_PORT = 65_535;
@@ -56,7 +59,7 @@ export function validateEnv(config: Record<string, unknown>): Environment {
   const parsedPort = Number(port);
   if (
     !Number.isInteger(parsedPort) ||
-    parsedPort < 1 ||
+    parsedPort < MIN_PORT ||
     parsedPort > MAX_PORT
   ) {
     throw new Error('PORT must be a valid port number');
@@ -84,7 +87,7 @@ export function validateEnv(config: Record<string, unknown>): Environment {
   }
 
   const parsedTbankRateLimit = Number(tbankRateLimit);
-  if (!Number.isInteger(parsedTbankRateLimit) || parsedTbankRateLimit < 1) {
+  if (!Number.isInteger(parsedTbankRateLimit) || parsedTbankRateLimit < MIN_REQUESTS_PER_SECOND) {
     throw new Error('TBANK_RATE_LIMIT_PER_SECOND must be a positive integer');
   }