Merged PR 2318: auth stabilisation: extract shared myportal auth guard helper

auth stabilisation: extract shared myportal auth guard helper

ntroduces a small shared SSR helper (resolveMyPortalAuthContext) to standardize common myportal auth/session guards (session presence, session user identity, and pinsUser cookie) with preserved reason-coded diagnostics and signin redirect behavior. Migrates exactly two loaders (pages/myportal/searchresults.js, pages/myportal/addresssearchresults.js) to use the helper while keeping loader-specific UPSTREAM_FAILURE and CONTACT_LOOKUP_FAILED logic unchanged.

Related work items: #23020

lib/auth/resolveMyPortalAuthContext.js

@@ -0,0 +1,58 @@
+import { getSession } from "next-auth/react";
+import { consoleLogger } from "../../actions/core/logger";
+
+const signinRedirect = {
+    destination: "/auth/signin",
+    permanent: false
+};
+
+const buildSigninRedirectResult = () => ({ redirect: signinRedirect });
+
+export async function resolveMyPortalAuthContext(ctx, options = {}) {
+    const {
+        loggerName = "MyPortalAuthGuard",
+        noSessionMessage = "myportal loader missing session; redirecting to signin",
+        noSessionUserMessage = "myportal loader missing session user identity; redirecting to signin",
+        noPinsUserMessage = "myportal loader missing pinsUser cookie; redirecting to signin"
+    } = options;
+
+    const session = await getSession(ctx);
+
+    if (!session) {
+        consoleLogger({
+            name: loggerName,
+            reasonCode: "NO_SESSION",
+            message: noSessionMessage
+        });
+        return { ok: false, redirect: buildSigninRedirectResult().redirect };
+    }
+
+    if (!session?.user?.id || !session?.user?.email) {
+        consoleLogger({
+            name: loggerName,
+            reasonCode: "NO_SESSION_USER",
+            message: noSessionUserMessage,
+            hasSessionUserId: !!session?.user?.id,
+            hasSessionUserEmail: !!session?.user?.email
+        });
+        return { ok: false, redirect: buildSigninRedirectResult().redirect };
+    }
+
+    const pinsUser = ctx?.req?.cookies?.pinsUser;
+    if (!pinsUser) {
+        consoleLogger({
+            name: loggerName,
+            reasonCode: "NO_PINSUSER_COOKIE",
+            message: noPinsUserMessage
+        });
+        return { ok: false, redirect: buildSigninRedirectResult().redirect };
+    }
+
+    return {
+        ok: true,
+        session,
+        sessionUserId: session.user.id,
+        sessionUserEmail: session.user.email,
+        pinsUser
+    };
+}