fix(auth): use public URL for magic-link redirects

apps/web/src/lib/application-url.test.ts

@@ -0,0 +1,9 @@
+import { describe, expect, it } from "vitest";
+import { applicationUrl } from "./application-url";
+
+describe("applicationUrl", () => {
+  it("builds browser redirects from the configured public application URL", () => {
+    expect(applicationUrl("/welcome", "https://portal.somc.club"))
+      .toEqual(new URL("https://portal.somc.club/welcome"));
+  });
+});

apps/web/src/lib/application-url.ts

@@ -0,0 +1,4 @@
+export function applicationUrl(path: string, baseUrl = process.env.APP_URL) {
+  if (!baseUrl) throw new Error("APP_URL is required to build public application URLs");
+  return new URL(path, baseUrl);
+}