Added logger and tests

lib/logger.ts

@@ -0,0 +1,31 @@
+/**
+ * Lightweight structured logger for server-side code.
+ *
+ * Wraps console.* with module prefixes and environment-aware filtering.
+ * Suppresses info/warn in test environment to reduce noise.
+ * Can be swapped for an external logging service (e.g. Axiom, Datadog) later.
+ */
+
+type LogLevel = 'info' | 'warn' | 'error'
+
+function shouldLog(level: LogLevel): boolean {
+  if (process.env.NODE_ENV === 'test') {
+    return level === 'error'
+  }
+  return true
+}
+
+export function createLogger(module: string) {
+  const prefix = `[${module}]`
+  return {
+    info(message: string, ...args: unknown[]) {
+      if (shouldLog('info')) console.log(prefix, message, ...args)
+    },
+    warn(message: string, ...args: unknown[]) {
+      if (shouldLog('warn')) console.warn(prefix, message, ...args)
+    },
+    error(message: string, ...args: unknown[]) {
+      if (shouldLog('error')) console.error(prefix, message, ...args)
+    },
+  }
+}