refactor(agent): rename metadata fields and enhance task configuration

- Rename 'metadata' columns to 'event_metadata' and 'finding_metadata' for clarity in database schema.
- Update AgentRunner to construct task configuration from task fields, ensuring default values are applied.
- Improve UI to handle potential null values for progress percentage and security score, enhancing user experience.

backend/alembic/versions/006_add_agent_tables.py

@@ -128,7 +128,7 @@ def upgrade() -> None:
         sa.Column('tokens_used', sa.Integer(), default=0),
         
         # 元数据
-        sa.Column('metadata', sa.JSON(), nullable=True),
+        sa.Column('event_metadata', sa.JSON(), nullable=True),
         
         # 序号
         sa.Column('sequence', sa.Integer(), default=0),
@@ -211,7 +211,7 @@ def upgrade() -> None:
         sa.Column('cvss_vector', sa.String(100), nullable=True),
         
         # 元数据
-        sa.Column('metadata', sa.JSON(), nullable=True),
+        sa.Column('finding_metadata', sa.JSON(), nullable=True),
         sa.Column('tags', sa.JSON(), nullable=True),
         
         # 去重标识

backend/app/services/agent/graph/runner.py

@@ -98,8 +98,8 @@ class AgentRunner:
         self.project_root = project_root
         
         # 事件管理
-        self.event_manager = EventManager(db, task.id)
-        self.event_emitter = AgentEventEmitter(self.event_manager)
+        self.event_manager = EventManager()
+        self.event_emitter = AgentEventEmitter(task.id, self.event_manager)
         
         # LLM 服务
         self.llm_service = LLMService()

frontend/src/pages/AgentAudit.tsx

@@ -345,10 +345,10 @@ export default function AgentAuditPage() {
                 <div className="w-32 h-2 bg-gray-800 rounded-full overflow-hidden">
                   <div
                     className="h-full bg-gradient-to-r from-cyan-600 to-cyan-400 transition-all duration-300"
-                    style={{ width: `${task.progress_percentage}%` }}
+                    style={{ width: `${task.progress_percentage ?? 0}%` }}
                   />
                 </div>
-                <span className="text-xs text-cyan-400">{task.progress_percentage.toFixed(0)}%</span>
+                <span className="text-xs text-cyan-400">{(task.progress_percentage ?? 0).toFixed(0)}%</span>
               </div>
               
               {/* Token 消耗 */}
@@ -438,11 +438,11 @@ export default function AgentAuditPage() {
               <div className="flex items-center justify-between text-xs">
                 <span className="text-gray-500">安全评分</span>
                 <span className={`font-bold ${
-                  task.security_score >= 80 ? "text-green-400" :
-                  task.security_score >= 60 ? "text-yellow-400" :
+                  (task.security_score ?? 0) >= 80 ? "text-green-400" :
+                  (task.security_score ?? 0) >= 60 ? "text-yellow-400" :
                   "text-red-400"
                 }`}>
-                  {task.security_score.toFixed(0)}/100
+                  {(task.security_score ?? 0).toFixed(0)}/100
                 </span>
               </div>
               <div className="flex items-center justify-between text-xs">