feat: complete Tasks 21-28 — backend integration, security hardening, UI tests & CI

- Add Apple Sign-In backend (JWKS verification, account linking, session management)
- Implement push notification deep linking with NotificationDeepLinkRouter
- Add jailbreak detection, runtime integrity monitoring, secure enclave service
- Implement OAuth social login, token refresh, and secure logout flows
- Add image caching (memory/disk), optimizer, upload queue, async semaphore
- Implement notification analytics, type preferences, and category setup
- Expand UI test suite with UITestBase, accessibility, auth flow, performance tests
- Add CI pipeline for iOS UI tests (3 device sizes) and performance benchmarks
- Restructure Xcode project to manual groups with KordantWidgets target
- Add SwiftLint, Swift Collections/Algorithms/GoogleSignIn dependencies
- Update project.yml for XcodeGen with new targets and configurations

web/src/server/services/user.service.ts

@@ -1,5 +1,6 @@
 import { TRPCError } from "@trpc/server";
 import { eq, and, isNull } from "drizzle-orm";
+import { createRemoteJWKSet, jwtVerify } from "jose";
 import { db } from "~/server/db";
 import { users, accounts } from "~/server/db/schema/auth";
 import { hashPassword, verifyPassword } from "~/server/auth/password";
@@ -67,6 +68,8 @@ export async function authenticateUser(
 }
 
 const GOOGLE_ISSUER = "https://accounts.google.com";
+const APPLE_ISSUER = "https://appleid.apple.com";
+const APPLE_JWKS_URL = new URL("https://appleid.apple.com/auth/keys");
 
 /**
  * Verifies a Google ID token using firebase-admin and returns the user.
@@ -207,6 +210,137 @@ export async function authenticateWithGoogle(idToken: string) {
   return { user, sessionToken: session.sessionToken, accessToken, refreshToken, isNewUser };
 }
 
+/**
+ * Verifies an Apple identity token and authenticates the user.
+ * If the user does not exist, creates a new account.
+ * If the user exists but has not linked Apple, links the provider.
+ */
+export async function authenticateWithApple(
+  identityToken: string,
+  authorizationCode: string,
+  userIdentifier?: string | null,
+) {
+  if (!identityToken) {
+    throw new TRPCError({
+      code: "BAD_REQUEST",
+      message: "Missing identity token",
+    });
+  }
+
+  // Verify Apple ID token using Apple's JWKS
+  let payload: { sub: string; email?: string; is_private_email?: string; };
+  try {
+    const JWKS = createRemoteJWKSet(APPLE_JWKS_URL);
+    const result = await jwtVerify(identityToken, JWKS, {
+      issuer: APPLE_ISSUER,
+      audience: process.env.IOS_BUNDLE_ID ?? "com.frenocorp.kordant",
+    });
+    payload = result.payload as unknown as { sub: string; email?: string; is_private_email?: string; };
+  } catch (err) {
+    throw new TRPCError({
+      code: "UNAUTHORIZED",
+      message: "Invalid Apple identity token",
+    });
+  }
+
+  const appleUserId = payload.sub;
+  const email = payload.email ?? null;
+
+  if (!email) {
+    throw new TRPCError({
+      code: "UNAUTHORIZED",
+      message: "Apple account has no email address",
+    });
+  }
+
+  // Check if this Apple account is already linked
+  const [existingAccount] = await db
+    .select()
+    .from(accounts)
+    .where(
+      and(
+        eq(accounts.provider, "apple"),
+        eq(accounts.providerAccountId, appleUserId),
+      ),
+    )
+    .limit(1);
+
+  let userId: string;
+  let isNewUser = false;
+
+  if (existingAccount) {
+    // Already linked — use the existing user
+    userId = existingAccount.userId;
+    isNewUser = false;
+
+    // Update tokens
+    await db
+      .update(accounts)
+      .set({
+        accessToken: identityToken,
+        refreshToken: authorizationCode,
+        updatedAt: new Date(),
+      })
+      .where(eq(accounts.id, existingAccount.id));
+  } else {
+    // Not linked — check if a user with this email exists
+    const [existingUserByEmail] = await db
+      .select()
+      .from(users)
+      .where(and(eq(users.email, email), isNull(users.deletedAt)))
+      .limit(1);
+
+    // Apple provides the user's first name and last name only on the initial sign-up
+    // We derive a display name from email if userIdentifier-based lookup doesn't work
+    const displayName = email.split("@")[0] ?? "User";
+
+    if (existingUserByEmail) {
+      // Link Apple to existing user
+      userId = existingUserByEmail.id;
+      isNewUser = false;
+      await db.insert(accounts).values({
+        userId,
+        provider: "apple",
+        providerAccountId: appleUserId,
+        accessToken: identityToken,
+        refreshToken: authorizationCode,
+      });
+    } else {
+      // Create new user with Apple
+      isNewUser = true;
+      const [newUser] = await db
+        .insert(users)
+        .values({
+          name: displayName,
+          email,
+          emailVerified: new Date(),
+        })
+        .returning();
+      userId = newUser.id;
+
+      await db.insert(accounts).values({
+        userId,
+        provider: "apple",
+        providerAccountId: appleUserId,
+        accessToken: identityToken,
+        refreshToken: authorizationCode,
+      });
+    }
+  }
+
+  // Create session and JWT
+  const session = await createSession(userId);
+  const accessToken = await signJWT({ sub: userId }, { expiresIn: "7d" });
+  const refreshToken = await signJWT({ sub: userId, type: "refresh" }, { expiresIn: "30d" });
+
+  const [user] = await db.select().from(users).where(eq(users.id, userId)).limit(1);
+  if (!user) {
+    throw new TRPCError({ code: "NOT_FOUND", message: "User not found after creation" });
+  }
+
+  return { user, sessionToken: session.sessionToken, accessToken, refreshToken, isNewUser };
+}
+
 /**
  * Refreshes an access token using a valid refresh token.
  */