feat: auth service + security audit fixes + cleanup legacy services

Major changes:
- Add auth-svc: JWT auth, register/login/refresh, password reset
- Add auth UI: modals, pages (/login, /register, /forgot-password)
- Add usage tracking (usage_metrics table, daily limits)
- Add tiered rate limiting (free/pro/business)
- Add LLM usage limits per tier

Security fixes:
- All repos now require userID for Update/Delete operations
- JWT middleware in chat-svc, llm-svc, agent-svc, discover-svc
- ErrNotFound/ErrForbidden errors for proper access control

Cleanup:
- Remove legacy TypeScript services/ directory
- Remove computer-svc (to be reimplemented)
- Remove old deploy/docker configs

New files:
- backend/cmd/auth-svc/main.go
- backend/internal/auth/{types,repository}.go
- backend/internal/usage/{types,repository}.go
- backend/pkg/middleware/{llm_limits,ratelimit_tiered}.go
- backend/webui/src/components/auth/*
- backend/webui/src/app/(auth)/*

Made-with: Cursor

backend/webui/src/lib/hooks/useChat.ts

@@ -1,8 +1,19 @@
 'use client';
 
 import { useState, useCallback, useRef } from 'react';
-import type { Message, Citation, Widget, StreamEvent } from '../types';
+import type { Message, Citation, Widget, StreamEvent, ChatAttachmentInfo } from '../types';
 import { streamChat, generateId } from '../api';
+import { getLanguageFromStorage } from '../contexts/LanguageContext';
+import type { SendOptions, ChatAttachment } from '@/components/ChatInput';
+
+function fileToDataUrl(file: File): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const reader = new FileReader();
+    reader.onload = () => resolve(reader.result as string);
+    reader.onerror = reject;
+    reader.readAsDataURL(file);
+  });
+}
 
 interface UseChatOptions {
   onError?: (error: Error) => void;
@@ -15,7 +26,11 @@ export function useChat(options: UseChatOptions = {}) {
   const [widgets, setWidgets] = useState<Widget[]>([]);
   const abortControllerRef = useRef<AbortController | null>(null);
 
-  const sendMessage = useCallback(async (content: string, mode: 'speed' | 'balanced' | 'quality' = 'balanced') => {
+  const sendMessage = useCallback(async (content: string, sendOptions?: SendOptions | 'speed' | 'balanced' | 'quality') => {
+    const mode = typeof sendOptions === 'string' ? sendOptions : sendOptions?.mode ?? 'balanced';
+    const webSearch = typeof sendOptions === 'object' ? sendOptions.webSearch : false;
+    const attachments = typeof sendOptions === 'object' ? sendOptions.attachments : [];
+    const locale = getLanguageFromStorage();
     if (!content.trim() || isLoading) return;
 
     const userMessage: Message = {
@@ -49,6 +64,21 @@ export function useChat(options: UseChatOptions = {}) {
         return acc;
       }, [] as [string, string][]);
 
+    const attachmentInfos = await Promise.all(
+      attachments.map(async (att) => {
+        let dataUrl: string | undefined;
+        if (att.type === 'image' || att.file.type.startsWith('image/')) {
+          dataUrl = await fileToDataUrl(att.file);
+        }
+        return {
+          name: att.file.name,
+          type: att.file.type,
+          size: att.file.size,
+          dataUrl,
+        };
+      })
+    );
+
     try {
       const stream = streamChat({
         message: {
@@ -58,7 +88,9 @@ export function useChat(options: UseChatOptions = {}) {
         },
         optimizationMode: mode,
         history,
-        locale: 'ru',
+        locale,
+        webSearch,
+        attachments: attachmentInfos.length > 0 ? attachmentInfos : undefined,
       });
 
       let fullContent = '';