feat: 实现 AI-First 代理系统

核心功能:
- AIAgent 模型：AI 代理身份管理
- AIOperationLog: AI 操作日志记录
- AITask: AI 异步任务系统
- AIWebhook: AI webhook 订阅

API 端点:
- POST /api/agents/auth/ - AI 代理认证
- GET/POST /api/agents/ - 代理管理
- GET /api/agent-logs/ - 操作日志查询
- GET/POST /api/agent-tasks/ - 任务管理
- GET/POST /api/agent-webhooks/ - Webhook 管理
- POST /api/batch/ - 批量操作

预置 AI 代理:
- content-moderator-ai: 内容审核 AI
- content-generator-ai: 内容生成 AI
- service-curator-ai: 服务推荐 AI
- analytics-ai: 数据分析 AI
- admin-ai: 管理员 AI

文档:
- AI_AGENT.md: AI-First 设计文档
- init_agents.py: AI 代理初始化脚本

测试:
- 认证系统测试通过
- JWT token 生成正常
- 权限系统工作正常

city-manual/backend/agents/admin.py

@@ -0,0 +1,107 @@
+from django.contrib import admin
+from .models import AIAgent, AIOperationLog, AITask, AIWebhook
+
+
+@admin.register(AIAgent)
+class AIAgentAdmin(admin.ModelAdmin):
+    list_display = ['agent_id', 'name', 'is_active', 'rate_limit', 'last_seen', 'created_at']
+    list_filter = ['is_active', 'permissions', 'created_at']
+    search_fields = ['agent_id', 'name', 'description']
+    readonly_fields = ['created_at', 'updated_at', 'last_seen']
+    
+    fieldsets = (
+        ('基本信息', {
+            'fields': ['agent_id', 'name', 'description', 'secret_key']
+        }),
+        ('权限配置', {
+            'fields': ['permissions'],
+            'description': '可用权限：read, write, review, delete, batch, analytics'
+        }),
+        ('速率限制', {
+            'fields': ['rate_limit', 'rate_limit_window'],
+            'description': 'rate_limit: 每小时请求数，rate_limit_window: 时间窗口（秒）'
+        }),
+        ('状态', {
+            'fields': ['is_active', 'last_seen']
+        }),
+        ('元数据', {
+            'fields': ['created_at', 'updated_at'],
+            'classes': ['collapse']
+        }),
+    )
+
+
+@admin.register(AIOperationLog)
+class AIOperationLogAdmin(admin.ModelAdmin):
+    list_display = ['agent', 'action', 'resource_type', 'resource_id', 'status', 'confidence', 'created_at']
+    list_filter = ['status', 'action', 'resource_type', 'created_at']
+    search_fields = ['agent__agent_id', 'action', 'resource_type']
+    readonly_fields = ['created_at']
+    date_hierarchy = 'created_at'
+    
+    fieldsets = (
+        ('操作信息', {
+            'fields': ['agent', 'action', 'resource_type', 'resource_id', 'status']
+        }),
+        ('AI 元数据', {
+            'fields': ['confidence', 'reasoning']
+        }),
+        ('请求/响应', {
+            'fields': ['request_data', 'response_data', 'error_message'],
+            'classes': ['collapse']
+        }),
+        ('性能', {
+            'fields': ['execution_time_ms', 'created_at'],
+            'classes': ['collapse']
+        }),
+    )
+
+
+@admin.register(AITask)
+class AITaskAdmin(admin.ModelAdmin):
+    list_display = ['task_id', 'agent', 'task_type', 'status', 'progress', 'created_at', 'completed_at']
+    list_filter = ['status', 'task_type', 'created_at']
+    search_fields = ['task_id', 'agent__agent_id', 'task_type']
+    readonly_fields = ['created_at', 'started_at', 'completed_at']
+    
+    fieldsets = (
+        ('任务信息', {
+            'fields': ['task_id', 'agent', 'task_type', 'status']
+        }),
+        ('进度', {
+            'fields': ['progress', 'processed_items', 'total_items']
+        }),
+        ('结果', {
+            'fields': ['result', 'error_message'],
+            'classes': ['collapse']
+        }),
+        ('回调', {
+            'fields': ['callback_url', 'callback_secret'],
+            'classes': ['collapse']
+        }),
+        ('时间', {
+            'fields': ['created_at', 'started_at', 'completed_at'],
+            'classes': ['collapse']
+        }),
+    )
+
+
+@admin.register(AIWebhook)
+class AIWebhookAdmin(admin.ModelAdmin):
+    list_display = ['agent', 'event', 'url', 'is_active', 'last_triggered', 'failure_count']
+    list_filter = ['event', 'is_active', 'created_at']
+    search_fields = ['agent__agent_id', 'url', 'event']
+    readonly_fields = ['created_at', 'last_triggered']
+    
+    fieldsets = (
+        ('Webhook 信息', {
+            'fields': ['agent', 'event', 'url', 'secret']
+        }),
+        ('状态', {
+            'fields': ['is_active', 'last_triggered', 'failure_count']
+        }),
+        ('元数据', {
+            'fields': ['created_at'],
+            'classes': ['collapse']
+        }),
+    )