[Issue #6785] Add new X-API-KEY to frontend (#6786)

## Summary

Fixes #6785 

## Changes proposed

Updated frontend to grab new X-API-KEY param from AWS param store & use
it when making calls to the backend.

## Context for reviewers

Used same implementation as we are already using for the old API. Left
it in because we want there to be a fallback as we roll out API GW.

## Validation steps

Author: btabaska

frontend/src/constants/environments.ts

@@ -6,6 +6,7 @@ const {
   SENDY_LIST_ID,
   API_URL,
   API_AUTH_TOKEN,
+  API_GW_AUTH,
   NEXT_BUILD,
   SESSION_SECRET,
   NEXT_PUBLIC_BASE_URL,
@@ -62,6 +63,7 @@ export const environment: { [key: string]: string } = {
   API_URL: API_URL || "",
   AUTH_LOGIN_URL: AUTH_LOGIN_URL || "",
   API_AUTH_TOKEN: API_AUTH_TOKEN || "",
+  API_GW_AUTH: API_GW_AUTH || "",
   GOOGLE_TAG_MANAGER_ID: "GTM-MV57HMHS",
   ENVIRONMENT,
   NEXT_BUILD: NEXT_BUILD || "false",

frontend/src/services/fetch/fetcherHelpers.ts

@@ -30,6 +30,10 @@ export interface HeadersDict {
 export function getDefaultHeaders(): HeadersDict {
   const headers: HeadersDict = {};
 
+  if (environment.API_GW_AUTH) {
+    headers["X-API-KEY"] = environment.API_GW_AUTH;
+  }
+
   if (environment.API_AUTH_TOKEN) {
     headers["X-AUTH"] = environment.API_AUTH_TOKEN;
   }

frontend/tests/services/fetch/FetcherHelpers.test.ts

@@ -85,3 +85,79 @@ describe("throwError", () => {
     });
   });
 });
+
+describe("getDefaultHeaders", () => {
+  let mockEnvironment: { [key: string]: string };
+
+  beforeEach(() => {
+    jest.resetModules();
+    mockEnvironment = {};
+
+    // Mock the environment module
+    jest.doMock("src/constants/environments", () => ({
+      environment: mockEnvironment,
+    }));
+  });
+
+  afterEach(() => {
+    jest.resetAllMocks();
+  });
+
+  it("includes Content-Type header by default", async () => {
+    const { getDefaultHeaders } = await import(
+      "src/services/fetch/fetcherHelpers"
+    );
+    const headers = getDefaultHeaders();
+    expect(headers["Content-Type"]).toEqual("application/json");
+  });
+
+  it("includes X-AUTH header when API_AUTH_TOKEN is set", async () => {
+    mockEnvironment.API_AUTH_TOKEN = "test-auth-token";
+    mockEnvironment.API_GW_AUTH = "";
+
+    const { getDefaultHeaders } = await import(
+      "src/services/fetch/fetcherHelpers"
+    );
+    const headers = getDefaultHeaders();
+    expect(headers["X-AUTH"]).toEqual("test-auth-token");
+    expect(headers["Content-Type"]).toEqual("application/json");
+  });
+
+  it("includes X-API-KEY header when API_GW_AUTH is set", async () => {
+    mockEnvironment.API_AUTH_TOKEN = "";
+    mockEnvironment.API_GW_AUTH = "test-api-key";
+
+    const { getDefaultHeaders } = await import(
+      "src/services/fetch/fetcherHelpers"
+    );
+    const headers = getDefaultHeaders();
+    expect(headers["X-API-KEY"]).toEqual("test-api-key");
+    expect(headers["Content-Type"]).toEqual("application/json");
+  });
+
+  it("includes both X-AUTH and X-API-KEY headers when both tokens are set", async () => {
+    mockEnvironment.API_AUTH_TOKEN = "test-auth-token";
+    mockEnvironment.API_GW_AUTH = "test-api-key";
+
+    const { getDefaultHeaders } = await import(
+      "src/services/fetch/fetcherHelpers"
+    );
+    const headers = getDefaultHeaders();
+    expect(headers["X-AUTH"]).toEqual("test-auth-token");
+    expect(headers["X-API-KEY"]).toEqual("test-api-key");
+    expect(headers["Content-Type"]).toEqual("application/json");
+  });
+
+  it("does not include auth headers when tokens are not set", async () => {
+    mockEnvironment.API_AUTH_TOKEN = "";
+    mockEnvironment.API_GW_AUTH = "";
+
+    const { getDefaultHeaders } = await import(
+      "src/services/fetch/fetcherHelpers"
+    );
+    const headers = getDefaultHeaders();
+    expect(headers["X-AUTH"]).toBeUndefined();
+    expect(headers["X-API-KEY"]).toBeUndefined();
+    expect(headers["Content-Type"]).toEqual("application/json");
+  });
+});

infra/frontend/app-config/env-config/environment_variables.tf

@@ -119,7 +119,7 @@ locals {
       manage_method     = "manual"
       secret_store_name = "/api/${var.environment}/api-jwt-public-key"
     },
-    API_AUTH_X_API_KEY = {
+    API_GW_AUTH = {
       manage_method     = "manual"
       secret_store_name = "/${var.app_name}/${var.environment}/X-API-KEY"
     },