fix: 修复多个关键问题

- 修复前端路由守卫：未登录时不显示提示，直接跳转登录页
- 修复API拦截器：401错误不显示提示，直接跳转
- 增强验证码显示：图片尺寸从120x40增加到200x80
- 增大验证码字体：从28号增加到48号
- 优化验证码字符：排除易混淆的0和1
- 减少干扰线：从5条减少到3条，添加背景色优化
- 增强登录API日志：添加详细的调试日志
- 增强验证码生成和验证日志
- 优化异常处理和错误追踪

影响文件：
- src/router/index.ts
- src/api/request.ts
- app/services/auth_service.py
- app/api/v1/auth.py
- app/schemas/user.py

测试状态：
- 前端构建通过
- 后端语法检查通过
- 验证码显示效果优化完成

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

app/models/system_config.py

@@ -0,0 +1,40 @@
+"""
+系统配置数据模型
+"""
+from datetime import datetime
+from sqlalchemy import Column, BigInteger, String, Text, Integer, DateTime, Boolean, Index
+from sqlalchemy.dialects.postgresql import JSONB
+from app.db.base import Base
+
+
+class SystemConfig(Base):
+    """系统配置表"""
+
+    __tablename__ = "system_configs"
+
+    id = Column(BigInteger, primary_key=True, index=True)
+    config_key = Column(String(100), unique=True, nullable=False, index=True, comment="配置键")
+    config_name = Column(String(200), nullable=False, comment="配置名称")
+    config_value = Column(Text, nullable=True, comment="配置值")
+    value_type = Column(String(20), default="string", nullable=False, comment="值类型: string/number/boolean/json")
+    category = Column(String(50), nullable=False, index=True, comment="配置分类")
+    description = Column(Text, nullable=True, comment="配置描述")
+    is_system = Column(Boolean, default=False, nullable=False, comment="是否系统配置")
+    is_encrypted = Column(Boolean, default=False, nullable=False, comment="是否加密存储")
+    validation_rule = Column(Text, nullable=True, comment="验证规则(JSON)")
+    options = Column(JSONB, nullable=True, comment="可选值配置")
+    default_value = Column(Text, nullable=True, comment="默认值")
+    sort_order = Column(Integer, default=0, nullable=False, comment="排序序号")
+    is_active = Column(Boolean, default=True, nullable=False, comment="是否启用")
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False)
+    updated_by = Column(BigInteger, nullable=True, comment="更新人ID")
+
+    # 索引
+    __table_args__ = (
+        Index("idx_system_config_category", "category"),
+        Index("idx_system_config_active", "is_active"),
+    )
+
+    def __repr__(self):
+        return f"<SystemConfig(id={self.id}, config_key={self.config_key}, config_name={self.config_name})>"