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/pages/AuthPage.tsx

@@ -0,0 +1,9 @@
+import { AuthPanel } from "../components/AuthPanel";
+
+export function AuthPage() {
+  return (
+    <main className="min-h-screen bg-gradient-to-b from-slate-900 via-slate-950 to-black p-4">
+      <AuthPanel />
+    </main>
+  );
+}

web/src/pages/ChatsPage.tsx

@@ -0,0 +1,45 @@
+import { useEffect } from "react";
+import { ChatList } from "../components/ChatList";
+import { MessageComposer } from "../components/MessageComposer";
+import { MessageList } from "../components/MessageList";
+import { useRealtime } from "../hooks/useRealtime";
+import { useAuthStore } from "../store/authStore";
+import { useChatStore } from "../store/chatStore";
+
+export function ChatsPage() {
+  const me = useAuthStore((s) => s.me);
+  const logout = useAuthStore((s) => s.logout);
+  const loadChats = useChatStore((s) => s.loadChats);
+  const activeChatId = useChatStore((s) => s.activeChatId);
+  const loadMessages = useChatStore((s) => s.loadMessages);
+
+  useRealtime();
+
+  useEffect(() => {
+    void loadChats();
+  }, [loadChats]);
+
+  useEffect(() => {
+    if (activeChatId) {
+      void loadMessages(activeChatId);
+    }
+  }, [activeChatId, loadMessages]);
+
+  return (
+    <main className="flex h-screen w-full bg-bg text-text">
+      <ChatList />
+      <section className="flex flex-1 flex-col">
+        <div className="flex items-center justify-between border-b border-slate-700 bg-panel px-4 py-3">
+          <p className="text-sm">Signed in as {me?.username}</p>
+          <button className="rounded bg-slate-700 px-3 py-1 text-sm" onClick={logout}>
+            Logout
+          </button>
+        </div>
+        <div className="min-h-0 flex-1">
+          <MessageList />
+        </div>
+        <MessageComposer />
+      </section>
+    </main>
+  );
+}