feat(ai): Agent Tool 扩展 — QueryPatientProfile + DisplayHint 新增 3 变体

- QueryPatientProfileTool: 查询患者档案摘要（年龄/性别/慢性病/用药/家族史）
- DisplayHint 新增 TrendChart/InsightCard/PatientProfile 变体
- 沙箱: Patient + MedicalStaff 添加 query_patient_profile

crates/erp-ai/src/agent/tool.rs

@@ -51,5 +51,19 @@ pub enum DisplayHint {
         level: String,
         message: String,
     },
+    TrendChart {
+        metrics: Vec<String>,
+        period: String,
+        summary: String,
+    },
+    InsightCard {
+        title: String,
+        severity: String,
+        items: Vec<String>,
+    },
+    PatientProfile {
+        chronic_conditions: Vec<String>,
+        medication_count: usize,
+    },
     Text,
 }