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>

alembic/env.py

@@ -0,0 +1,66 @@
+"""
+Alembic环境配置
+"""
+from logging.config import fileConfig
+from sqlalchemy import engine_from_config, pool
+from alembic import context
+import sys
+from pathlib import Path
+
+# 添加项目根目录到Python路径
+sys.path.append(str(Path(__file__).resolve().parents[1]))
+
+from app.core.config import settings
+from app.db.base import Base
+from app.models import user  # 导入所有模型
+
+# Alembic配置对象
+config = context.config
+
+# 设置数据库URL
+config.set_main_option("sqlalchemy.url", settings.DATABASE_URL.replace("+asyncpg", ""))
+
+# 解析日志配置
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# 模型的元数据
+target_metadata = Base.metadata
+
+
+def run_migrations_offline() -> None:
+    """离线模式运行迁移"""
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    """在线模式运行迁移"""
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()