Phase 10: Per-User Rate Limits — messages + tokens, quota UI, admin usage

Backend:
- max_ai_messages_per_day + max_ai_tokens_per_day on User model (nullable, override)
- Migration 008: add columns + seed default settings (100 msgs, 500K tokens)
- usage_service: count today's messages + tokens, check quota, get limits
- GET /chats/quota returns usage vs limits + reset time
- POST /chats/{id}/messages checks quota before streaming (429 if exceeded)
- Admin user schemas expose both limit fields
- GET /admin/usage returns per-user daily message + token counts
- admin_user_service allows updating both limit fields

Frontend:
- Chat header shows "X/Y messages · XK/YK tokens" with red highlight at limit
- Quota refreshes every 30s via TanStack Query
- Admin usage page with table: user, messages today, tokens today
- Route + sidebar entry for admin usage
- English + Russian translations

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/public/locales/en/translation.json

@@ -39,7 +39,8 @@
     "skills": "Skills",
     "personal_context": "My Context",
     "pdf": "PDF Reports",
-    "pdf_templates": "Templates"
+    "pdf_templates": "Templates",
+    "usage": "Usage"
   },
   "dashboard": {
     "welcome": "Welcome, {{name}}",
@@ -56,7 +57,9 @@
     "unarchive": "Unarchive",
     "delete_confirm": "Are you sure you want to delete this chat?",
     "limit_reached": "Chat limit reached",
-    "streaming": "AI is thinking..."
+    "streaming": "AI is thinking...",
+    "quota_messages": "{{used}}/{{limit}} messages",
+    "quota_tokens": "{{used}}K/{{limit}}K tokens"
   },
   "admin": {
     "context_editor": "Primary Context Editor",
@@ -197,6 +200,13 @@
     "default_max_chats": "Default Max Chats",
     "default_max_chats_desc": "Default chat limit for new users"
   },
+  "admin_usage": {
+    "title": "Usage Statistics",
+    "user": "User",
+    "messages": "Messages Today",
+    "tokens": "Tokens Today",
+    "no_data": "No usage data available."
+  },
   "common": {
     "loading": "Loading...",
     "error": "An error occurred",

frontend/public/locales/ru/translation.json

@@ -39,7 +39,8 @@
     "skills": "Навыки",
     "personal_context": "Мой контекст",
     "pdf": "PDF отчёты",
-    "pdf_templates": "Шаблоны"
+    "pdf_templates": "Шаблоны",
+    "usage": "Использование"
   },
   "dashboard": {
     "welcome": "Добро пожаловать, {{name}}",
@@ -56,7 +57,9 @@
     "unarchive": "Разархивировать",
     "delete_confirm": "Вы уверены, что хотите удалить этот чат?",
     "limit_reached": "Достигнут лимит чатов",
-    "streaming": "ИИ думает..."
+    "streaming": "ИИ думает...",
+    "quota_messages": "{{used}}/{{limit}} сообщений",
+    "quota_tokens": "{{used}}K/{{limit}}K токенов"
   },
   "admin": {
     "context_editor": "Редактор основного контекста",
@@ -197,6 +200,13 @@
     "default_max_chats": "Лимит чатов по умолчанию",
     "default_max_chats_desc": "Лимит чатов для новых пользователей"
   },
+  "admin_usage": {
+    "title": "Статистика использования",
+    "user": "Пользователь",
+    "messages": "Сообщения сегодня",
+    "tokens": "Токены сегодня",
+    "no_data": "Данных пока нет."
+  },
   "common": {
     "loading": "Загрузка...",
     "error": "Произошла ошибка",

frontend/src/api/chats.ts

@@ -56,6 +56,21 @@ export async function deleteChat(chatId: string): Promise<void> {
   await api.delete(`/chats/${chatId}`);
 }
 
+export interface QuotaInfo {
+  messages_used: number;
+  message_limit: number;
+  tokens_used: number;
+  token_limit: number;
+  messages_exceeded: boolean;
+  tokens_exceeded: boolean;
+  resets_at: string;
+}
+
+export async function getQuota(): Promise<QuotaInfo> {
+  const { data } = await api.get<QuotaInfo>("/chats/quota");
+  return data;
+}
+
 export async function getMessages(
   chatId: string,
   limit = 50,

frontend/src/components/chat/chat-window.tsx

@@ -1,9 +1,11 @@
 import { useEffect, useRef } from "react";
 import { useTranslation } from "react-i18next";
+import { useQuery } from "@tanstack/react-query";
 import { MessageBubble } from "./message-bubble";
 import { MessageInput } from "./message-input";
 import { SkillSelector } from "./skill-selector";
 import { useChatStore } from "@/stores/chat-store";
+import { getQuota } from "@/api/chats";
 import { MessageSquare } from "lucide-react";
 
 interface ChatWindowProps {
@@ -16,6 +18,11 @@ export function ChatWindow({ onSendMessage, onChangeSkill, currentSkillId }: Cha
   const { t } = useTranslation();
   const { messages, isStreaming, streamingContent, currentChatId } = useChatStore();
   const bottomRef = useRef<HTMLDivElement>(null);
+  const { data: quota } = useQuery({
+    queryKey: ["chat-quota"],
+    queryFn: getQuota,
+    refetchInterval: 30000,
+  });
 
   useEffect(() => {
     bottomRef.current?.scrollIntoView({ behavior: "smooth" });
@@ -32,15 +39,25 @@ export function ChatWindow({ onSendMessage, onChangeSkill, currentSkillId }: Cha
 
   return (
     <div className="flex h-full flex-col">
-      {onChangeSkill && (
+      {(onChangeSkill || quota) && (
         <div className="flex items-center gap-2 border-b px-4 py-2">
-          <div className="w-48">
-            <SkillSelector
-              value={currentSkillId ?? null}
-              onChange={onChangeSkill}
-              disabled={isStreaming}
-            />
-          </div>
+          {quota && (
+            <span className={`text-xs ${quota.messages_exceeded || quota.tokens_exceeded ? "text-destructive" : "text-muted-foreground"}`}>
+              {t("chat.quota_messages", { used: quota.messages_used, limit: quota.message_limit })}
+              {" · "}
+              {t("chat.quota_tokens", { used: Math.round(quota.tokens_used / 1000), limit: Math.round(quota.token_limit / 1000) })}
+            </span>
+          )}
+          <div className="flex-1" />
+          {onChangeSkill && (
+            <div className="w-48">
+              <SkillSelector
+                value={currentSkillId ?? null}
+                onChange={onChangeSkill}
+                disabled={isStreaming}
+              />
+            </div>
+          )}
         </div>
       )}
       <div className="flex-1 overflow-y-auto p-4 space-y-4">

frontend/src/components/layout/sidebar.tsx

@@ -32,6 +32,7 @@ const adminItems = [
   { key: "admin_users", to: "/admin/users", label: "layout.users" },
   { key: "admin_settings", to: "/admin/settings", label: "layout.settings" },
   { key: "admin_templates", to: "/admin/pdf-templates", label: "layout.pdf_templates" },
+  { key: "admin_usage", to: "/admin/usage", label: "layout.usage" },
 ];
 
 export function Sidebar() {

frontend/src/pages/admin/usage.tsx

@@ -0,0 +1,71 @@
+import { Navigate } from "react-router-dom";
+import { useTranslation } from "react-i18next";
+import { useQuery } from "@tanstack/react-query";
+import { useAuthStore } from "@/stores/auth-store";
+import api from "@/api/client";
+import { cn } from "@/lib/utils";
+
+interface UserUsage {
+  user_id: string;
+  username: string;
+  messages_today: number;
+  message_limit: number;
+  tokens_today: number;
+  token_limit: number;
+}
+
+export function AdminUsagePage() {
+  const { t } = useTranslation();
+  const user = useAuthStore((s) => s.user);
+
+  const { data } = useQuery({
+    queryKey: ["admin-usage"],
+    queryFn: async () => {
+      const { data } = await api.get<{ users: UserUsage[] }>("/admin/usage");
+      return data.users;
+    },
+    refetchInterval: 30000,
+  });
+
+  if (user?.role !== "admin") return <Navigate to="/" replace />;
+
+  const users = data || [];
+
+  return (
+    <div className="space-y-4">
+      <h1 className="text-2xl font-semibold">{t("admin_usage.title")}</h1>
+
+      <div className="rounded-lg border">
+        <table className="w-full text-sm">
+          <thead>
+            <tr className="border-b bg-muted/50">
+              <th className="px-4 py-3 text-left font-medium">{t("admin_usage.user")}</th>
+              <th className="px-4 py-3 text-right font-medium">{t("admin_usage.messages")}</th>
+              <th className="px-4 py-3 text-right font-medium">{t("admin_usage.tokens")}</th>
+            </tr>
+          </thead>
+          <tbody>
+            {users.map((u) => (
+              <tr key={u.user_id} className="border-b last:border-0">
+                <td className="px-4 py-3">{u.username}</td>
+                <td className="px-4 py-3 text-right">
+                  <span className={cn(u.messages_today >= u.message_limit && "text-destructive font-medium")}>
+                    {u.messages_today} / {u.message_limit}
+                  </span>
+                </td>
+                <td className="px-4 py-3 text-right">
+                  <span className={cn(u.tokens_today >= u.token_limit && "text-destructive font-medium")}>
+                    {Math.round(u.tokens_today / 1000)}K / {Math.round(u.token_limit / 1000)}K
+                  </span>
+                </td>
+              </tr>
+            ))}
+            {users.length === 0 && (
+              <tr><td colSpan={3} className="px-4 py-8 text-center text-muted-foreground">{t("admin_usage.no_data")}</td></tr>
+            )}
+          </tbody>
+        </table>
+      </div>
+    </div>
+  );
+}

frontend/src/routes.tsx

@@ -16,6 +16,7 @@ import { PdfPage } from "@/pages/pdf";
 import { AdminUsersPage } from "@/pages/admin/users";
 import { AdminSettingsPage } from "@/pages/admin/settings";
 import { AdminPdfTemplatesPage } from "@/pages/admin/pdf-templates";
+import { AdminUsagePage } from "@/pages/admin/usage";
 import { NotFoundPage } from "@/pages/not-found";
 
 export const router = createBrowserRouter([
@@ -47,6 +48,7 @@ export const router = createBrowserRouter([
           { path: "admin/users", element: <AdminUsersPage /> },
           { path: "admin/settings", element: <AdminSettingsPage /> },
           { path: "admin/pdf-templates", element: <AdminPdfTemplatesPage /> },
+          { path: "admin/usage", element: <AdminUsagePage /> },
         ],
       },
     ],