权限监控与管理界面全面美化

重新设计权限系统所有 UI 组件的视觉风格，统一配色、圆角、阴影和交互动效：
- 实时概览：统计卡片加图标和渐变色条，健康评分改为环形进度，告警改为卡片式
- 趋势分析：图表卡片加彩色图标标识，ECharts 配色升级为渐变面积填充
- 访问日志：指标卡片带图标，日志审计改为卡片式入口，IP排行前三高亮
- IP属地：工具栏重设计，排行列表前三渐变高亮，指标卡片统一新风格
- 系统级权限：从 el-table 改为自定义卡片列表，模块块独立圆角卡片
- 项目权限配置：空状态引导优化，成员表格加头像，工具栏加背景容器
- 角色概览卡片：加进度条可视化，hover 微动效
- 接口权限矩阵：工具栏分离布局，表格圆角包裹
- 角色管理抽屉：侧边栏选中态渐变，操作行 hover 高亮

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

backend/app/models/permission_access_log.py

@@ -0,0 +1,43 @@
+"""权限访问日志模型"""
+
+from __future__ import annotations
+
+import uuid
+from datetime import datetime
+from typing import Optional
+
+from sqlalchemy import Boolean, DateTime, Float, ForeignKey, Index, String
+from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy.orm import Mapped, mapped_column
+from sqlalchemy.sql import func
+
+from app.db.base_class import Base
+
+
+class PermissionAccessLog(Base):
+    __tablename__ = "permission_access_logs"
+    __table_args__ = (
+        Index("ix_perm_log_study_created", "study_id", "created_at"),
+        Index("ix_perm_log_user_created", "user_id", "created_at"),
+        Index("ix_perm_log_endpoint_created", "endpoint_key", "created_at"),
+        Index("ix_perm_log_created_at", "created_at"),
+        Index("ix_perm_log_allowed", "allowed", "created_at"),
+    )
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
+    )
+    study_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), ForeignKey("studies.id"), nullable=False
+    )
+    user_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), ForeignKey("users.id"), nullable=False
+    )
+    endpoint_key: Mapped[str] = mapped_column(String(100), nullable=False)
+    role: Mapped[str] = mapped_column(String(30), nullable=False)
+    allowed: Mapped[bool] = mapped_column(Boolean, nullable=False)
+    elapsed_ms: Mapped[float] = mapped_column(Float, nullable=False)
+    ip_address: Mapped[Optional[str]] = mapped_column(String(45), nullable=True)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now()
+    )