Add byte-compatible Auth & SSO core primitives

Pure, unit-tested primitives the AtomCMS->Next.js login must reproduce exactly
(verified now with round-trip + known vectors; full end-to-end check deferred
until a real DB + APP_KEY + live emulator are available):

- password.ts: argon2id (m=65536,t=4,p=1 via hash-wasm) + bcrypt ($2y$ accepted)
  verify, and the md5->argon2id on-login upgrade gated by convert_passwords
  (mirrors RedirectIfTwoFactorAuthenticatable).
- sso-ticket.ts: '{hotel_name without spaces}-{uuidv4}' written to auth_ticket +
  ip_current (mirrors User::ssoTicket()).
- laravel-encrypter.ts: AES-256-CBC + HMAC-SHA256 payload compatible with
  Laravel encrypt()/encryptString (for existing 2FA secrets) incl. PHP string
  (de)serialization.
- totp.ts: otplib Google2FA-compatible TOTP verify (SHA1/6/30).

Libs: hash-wasm + bcryptjs + otplib (pure JS/WASM, no native build). 28 tests.

src/lib/auth/password.test.ts

@@ -0,0 +1,69 @@
+import { hash as bcryptHash } from "bcryptjs";
+import { describe, expect, it } from "vitest";
+import {
+  checkLogin,
+  hashPassword,
+  isMd5Of,
+  md5Hex,
+  verifyPassword,
+} from "./password";
+
+describe("md5Hex", () => {
+  it("matches PHP md5() on canonical vectors", () => {
+    expect(md5Hex("")).toBe("d41d8cd98f00b204e9800998ecf8427e");
+    expect(md5Hex("abc")).toBe("900150983cd24fb0d6963f7d28e17f72");
+  });
+});
+
+describe("argon2id", () => {
+  it("hashes with the AtomCMS params (m=65536,t=4,p=1) and round-trips", async () => {
+    const h = await hashPassword("s3cret!");
+    expect(h).toMatch(/^\$argon2id\$v=19\$m=65536,t=4,p=1\$/);
+    expect(await verifyPassword("s3cret!", h)).toBe(true);
+    expect(await verifyPassword("wrong", h)).toBe(false);
+  });
+});
+
+describe("bcrypt", () => {
+  it("verifies a bcrypt hash and accepts the PHP $2y$ prefix", async () => {
+    const h = await bcryptHash("hunter2", 10); // bcryptjs emits $2a$
+    expect(await verifyPassword("hunter2", h)).toBe(true);
+    // PHP stores $2y$ — bcryptjs must accept it as equivalent.
+    const phpStyle = h.replace(/^\$2[ab]\$/, "$2y$");
+    expect(await verifyPassword("hunter2", phpStyle)).toBe(true);
+    expect(await verifyPassword("nope", h)).toBe(false);
+  });
+});
+
+describe("isMd5Of", () => {
+  it("detects a legacy md5 password", () => {
+    expect(isMd5Of("habbo", md5Hex("habbo"))).toBe(true);
+    expect(isMd5Of("habbo", md5Hex("other"))).toBe(false);
+    expect(isMd5Of("habbo", "not-a-hash")).toBe(false);
+  });
+});
+
+describe("checkLogin", () => {
+  it("upgrades a legacy md5 hash to argon2id when conversion is enabled", async () => {
+    const stored = md5Hex("oldpass");
+    const res = await checkLogin("oldpass", stored, { convertPasswords: true });
+    expect(res.valid).toBe(true);
+    expect(res.upgradedHash).toMatch(/^\$argon2id\$/);
+    // The upgraded hash verifies the same password.
+    expect(await verifyPassword("oldpass", res.upgradedHash as string)).toBe(true);
+  });
+
+  it("does NOT upgrade md5 when conversion is disabled", async () => {
+    const stored = md5Hex("oldpass");
+    const res = await checkLogin("oldpass", stored, { convertPasswords: false });
+    expect(res.valid).toBe(false);
+    expect(res.upgradedHash).toBeUndefined();
+  });
+
+  it("validates an existing argon2id hash with no upgrade", async () => {
+    const stored = await hashPassword("modern");
+    const res = await checkLogin("modern", stored, { convertPasswords: true });
+    expect(res.valid).toBe(true);
+    expect(res.upgradedHash).toBeUndefined();
+  });
+});