refactor(config): add env parsing helpers and tighten startup validation

src/common/config/env.utils.ts

@@ -0,0 +1,66 @@
+export function parseBoolean(
+  value: string | undefined,
+  fallback: boolean,
+): boolean {
+  if (value === undefined) {
+    return fallback;
+  }
+
+  const normalized = value.trim().toLowerCase();
+  if (['true', '1', 'yes', 'y', 'on'].includes(normalized)) {
+    return true;
+  }
+
+  if (['false', '0', 'no', 'n', 'off'].includes(normalized)) {
+    return false;
+  }
+
+  return fallback;
+}
+
+export function parsePositiveInteger(
+  value: string | undefined,
+  fallback: number,
+): number {
+  if (!value) {
+    return fallback;
+  }
+
+  const parsed = Number(value);
+  if (!Number.isFinite(parsed) || parsed <= 0) {
+    return fallback;
+  }
+
+  return Math.floor(parsed);
+}
+
+export function parseCsvList(value: string | undefined): string[] {
+  if (!value) {
+    return [];
+  }
+
+  return value
+    .split(',')
+    .map((item) => item.trim())
+    .filter((item) => item.length > 0);
+}
+
+export function isLikelyHttpOrigin(origin: string): boolean {
+  try {
+    const parsed = new URL(origin);
+    return parsed.protocol === 'http:' || parsed.protocol === 'https:';
+  } catch {
+    return false;
+  }
+}
+
+export function parseRedisRequired(config: {
+  nodeEnv?: string;
+  redisRequired?: string;
+}): boolean {
+  if (config.redisRequired === undefined) {
+    return config.nodeEnv === 'production';
+  }
+
+  return parseBoolean(config.redisRequired, false);
+}