chore(config): centralize feature settings

lib/config/environment.test.ts

@@ -0,0 +1,31 @@
+import { describe, expect, test } from "bun:test";
+import {
+  optionalEnvironmentValue,
+  readFeatureEnvironment,
+  requiredEnvironmentUrl,
+  requiredEnvironmentValue,
+} from "@/lib/config/environment";
+
+describe("feature environment configuration", () => {
+  test("returns trimmed required and optional values", () => {
+    const environment = { REQUIRED: " value ", OPTIONAL: " optional " };
+    expect(requiredEnvironmentValue("REQUIRED", environment)).toBe("value");
+    expect(optionalEnvironmentValue("OPTIONAL", environment)).toBe("optional");
+    expect(optionalEnvironmentValue("MISSING", environment)).toBeNull();
+  });
+
+  test("reports the feature and missing variable", () => {
+    expect(() =>
+      readFeatureEnvironment("Discord", ["TOKEN", "GUILD"] as const, {
+        TOKEN: "token",
+      }),
+    ).toThrow("Discord is not configured: Missing required environment variable: GUILD");
+  });
+
+  test("accepts absolute URLs and removes a trailing slash", () => {
+    expect(requiredEnvironmentUrl("BASE_URL", { BASE_URL: "https://example.com/" }))
+      .toBe("https://example.com");
+    expect(() => requiredEnvironmentUrl("BASE_URL", { BASE_URL: "/relative" }))
+      .toThrow("must be an absolute URL");
+  });
+});