feat: add Z.AI env support and live test

src/infra/env.ts

@@ -0,0 +1,9 @@
+export function normalizeZaiEnv(): void {
+  if (!process.env.ZAI_API_KEY?.trim() && process.env.Z_AI_API_KEY?.trim()) {
+    process.env.ZAI_API_KEY = process.env.Z_AI_API_KEY;
+  }
+}
+
+export function normalizeEnv(): void {
+  normalizeZaiEnv();
+}