refactor: migrate frontend to React + Tailwind, add Docker + tests

Replace the vanilla-TS innerHTML frontend with a type-checked React
component tree (React 19 + Tailwind v4 + Vite).

Frontend:
- 14 components: Header, Stepper, LoginPage, LoginModal, SignPage,
  DropZone, DevicePicker, ProgressCard, SavedAccountsList, TrustModal,
  TwoFactorModal, Button, Field, Chip, Modal
- lib/ extracts: storage (10 localStorage keys preserved), pair-record,
  account-session, log-parser, ids, use-log hook
- flows/ encapsulate async pair/login/sign/install with dependency injection
- Accounts page as main view with Add Account modal
- Fullscreen progress overlay during sign/install
- Account selector + device picker on Sign page
- Security notice in login modal (server trust warning)
- All addLog calls mirrored to console.log for devtools debugging

Build:
- bun run dev: submodule init + install + wasm dist + vite + wrangler
- bun run setup: one-shot project bootstrap
- Docker: multi-stage bun build → nginx on :3000
- build:wasm:dist copies pre-built src→dist (no Rust/Emscripten needed)
- jszip/node-forge/fflate pre-bundled for CJS→ESM conversion

Tests:
- 163 vitest tests (happy-dom): all lib, components, App integration,
  WASM dist artifact checks, libcurl Apple connectivity, anisette init
  error handling

Cleanup:
- Delete yarn.lock (bun.lock canonical), expand .gitignore
- Remove README.zh.md, rewrite README.md + AGENTS.md
- Update libcurl.js submodule to f65d440 (CI build artifacts)

frontend/src/components/LoginPage.tsx

@@ -0,0 +1,55 @@
+import { Button } from './ui/Button';
+import { SavedAccountsList } from './SavedAccountsList';
+import type { StoredAccountSummary } from '../lib/account-session';
+
+interface LoginPageProps {
+  loggedIn: boolean;
+  savedAccounts: StoredAccountSummary[];
+  activeAccountKey: string | null;
+  cachedAccountKeys: Set<string>;
+  onSwitchAccount: (summary: StoredAccountSummary) => void;
+  onDeleteAccount: (summary: StoredAccountSummary) => void;
+  onAddAccount: () => void;
+  onGoToSignPage: () => void;
+}
+
+export function LoginPage({
+  loggedIn,
+  savedAccounts,
+  activeAccountKey,
+  cachedAccountKeys,
+  onSwitchAccount,
+  onDeleteAccount,
+  onAddAccount,
+  onGoToSignPage,
+}: LoginPageProps) {
+  return (
+    <section className="space-y-6 anim-in">
+      <div className="flex items-start justify-between gap-4">
+        <div>
+          <h1 className="text-[clamp(1.75rem,3.5vw,2.1rem)] font-semibold tracking-tight text-ink">Accounts</h1>
+          <p className="mt-1 text-[14px] text-muted">Add your Apple Developer account here to sign and install apps.</p>
+        </div>
+        <Button variant="primary" onClick={onAddAccount} className="shrink-0">
+          Add Account
+        </Button>
+      </div>
+
+      <SavedAccountsList
+        accounts={savedAccounts}
+        activeKey={activeAccountKey}
+        cachedKeys={cachedAccountKeys}
+        onSwitch={onSwitchAccount}
+        onDelete={onDeleteAccount}
+      />
+
+      {loggedIn && (
+        <div className="flex justify-end">
+          <Button variant="ghost" onClick={onGoToSignPage}>
+            Sign &amp; Install →
+          </Button>
+        </div>
+      )}
+    </section>
+  );
+}