feat: 登录验证 + 邀请码注册 + 用量监控后台

- 新增用户认证系统（登录/登出/邀请码注册）
- 新增管理后台（邀请码管理/用户管理/使用记录/用量统计）
- 合成接口加登录验证，每次调用记录用户和稿件内容
- SQLite存储用户数据和使用日志
- 默认admin账号: simonkoson

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/app/routes/tts_synthesize.py

@@ -1,56 +1,63 @@
-from flask import Blueprint, request, jsonify
+from flask import Blueprint, request, jsonify, session
 import base64
 import os
-import requests
 from app.services.minimax_service import synthesize_minimax
 from app.services.cosyvoice_service import synthesize_cosyvoice
+from app.routes.auth import login_required
+from app.db import get_db
 
 bp = Blueprint('tts', __name__, url_prefix='/api')
 
-MINIMAX_API_KEY = os.getenv('MINIMAX_API_KEY', '')
-MINIMAX_API_URL = 'https://api.minimax.chat/v1/t2a_v2'
-
-COSYVOICE_API_URL = os.getenv('COSYVOICE_API_URL', 'http://127.0.0.1:5001/v1/audio/synthesis')
 
 @bp.route('/synthesize', methods=['POST'])
+@login_required
 def synthesize():
     data = request.get_json()
-    
+
     if not data or 'text' not in data:
         return jsonify({'error': '缺少text参数'}), 400
-    
+
     text = data.get('text')
     engine = data.get('engine', 'minimax')
     speed = data.get('speed', 1.0)
     pitch = data.get('pitch', 0)
     volume = data.get('volume', 1.0)
-    instruction = data.get('instruction')  # 用于CosyVoice的情绪指令
-    emotion = data.get('emotion', 'neutral')  # 用于MiniMax的情绪参数
-    
+    instruction = data.get('instruction')
+    emotion = data.get('emotion', 'neutral')
+
     if not text.strip():
         return jsonify({'error': '文本不能为空'}), 400
-    
+
     if len(text) > 2000:
         return jsonify({'error': '文本不能超过2000字'}), 400
-    
+
     try:
         if engine == 'cosyvoice':
             audio_data = synthesize_cosyvoice(
-                text=text,
-                speed=speed,
-                pitch=pitch,
-                volume=volume,
-                instruction=instruction
+                text=text, speed=speed, pitch=pitch,
+                volume=volume, instruction=instruction
             )
         else:
             audio_data = synthesize_minimax(
-                text=text,
-                speed=speed,
-                pitch=pitch,
-                volume=volume,
-                emotion=emotion
+                text=text, speed=speed, pitch=pitch,
+                volume=volume, emotion=emotion
             )
-        
+
+        # 记录使用日志
+        try:
+            conn = get_db()
+            conn.execute(
+                '''INSERT INTO usage_logs
+                   (user_id, username, display_name, text_content, text_length, engine, emotion)
+                   VALUES (?, ?, ?, ?, ?, ?, ?)''',
+                (session['user_id'], session['username'], session['display_name'],
+                 text, len(text), engine, emotion)
+            )
+            conn.commit()
+            conn.close()
+        except Exception:
+            pass  # 日志写入失败不影响正常合成
+
         return jsonify({
             'success': True,
             'audio': base64.b64encode(audio_data).decode('utf-8')