Add web client and containerized deployment stack

Web client:

- Added React + TypeScript + Vite + Tailwind application in web/.

- Implemented auth, chat list, chat messages, typing indicators, file uploads, and voice recording/playback.

- Added typed API layer, Zustand stores, and realtime websocket hook integration.

Containerization:

- Added backend Dockerfile and project .dockerignore.

- Added web multi-stage Dockerfile with nginx static hosting and API/WS reverse proxy.

- Added full docker-compose stack with postgres, redis, minio, backend, worker, mailpit, and web.

- Added MinIO bucket bootstrap init job and updated README with Docker quick-start.

web/src/components/AuthPanel.tsx

@@ -0,0 +1,58 @@
+import { FormEvent, useState } from "react";
+import { registerRequest } from "../api/auth";
+import { useAuthStore } from "../store/authStore";
+
+type Mode = "login" | "register";
+
+export function AuthPanel() {
+  const login = useAuthStore((s) => s.login);
+  const loading = useAuthStore((s) => s.loading);
+  const [mode, setMode] = useState<Mode>("login");
+  const [email, setEmail] = useState("");
+  const [username, setUsername] = useState("");
+  const [password, setPassword] = useState("");
+  const [error, setError] = useState<string | null>(null);
+  const [success, setSuccess] = useState<string | null>(null);
+
+  async function onSubmit(event: FormEvent) {
+    event.preventDefault();
+    setError(null);
+    setSuccess(null);
+    try {
+      if (mode === "register") {
+        await registerRequest(email, username, password);
+        setSuccess("Registered. Check email verification, then login.");
+        setMode("login");
+        return;
+      }
+      await login(email, password);
+    } catch {
+      setError("Auth request failed.");
+    }
+  }
+
+  return (
+    <div className="mx-auto mt-16 w-full max-w-md rounded-xl bg-panel p-6 shadow-xl">
+      <div className="mb-4 flex gap-2">
+        <button className={`rounded px-3 py-2 ${mode === "login" ? "bg-accent text-black" : "bg-slate-700"}`} onClick={() => setMode("login")}>
+          Login
+        </button>
+        <button className={`rounded px-3 py-2 ${mode === "register" ? "bg-accent text-black" : "bg-slate-700"}`} onClick={() => setMode("register")}>
+          Register
+        </button>
+      </div>
+      <form className="space-y-3" onSubmit={onSubmit}>
+        <input className="w-full rounded bg-slate-800 px-3 py-2" placeholder="Email" value={email} onChange={(e) => setEmail(e.target.value)} />
+        {mode === "register" && (
+          <input className="w-full rounded bg-slate-800 px-3 py-2" placeholder="Username" value={username} onChange={(e) => setUsername(e.target.value)} />
+        )}
+        <input className="w-full rounded bg-slate-800 px-3 py-2" placeholder="Password" type="password" value={password} onChange={(e) => setPassword(e.target.value)} />
+        <button className="w-full rounded bg-accent px-3 py-2 font-semibold text-black disabled:opacity-50" disabled={loading} type="submit">
+          {mode === "login" ? "Sign in" : "Create account"}
+        </button>
+      </form>
+      {error ? <p className="mt-3 text-sm text-red-400">{error}</p> : null}
+      {success ? <p className="mt-3 text-sm text-emerald-400">{success}</p> : null}
+    </div>
+  );
+}