fix(health+web): PII 解密日志 + 负年龄防护 + 随访页面中文 placeholder

- helper.rs: 提取 decrypt_field 辅助函数，解密失败时输出 warn 日志而非静默返回 None
- format.ts: calcAge 负年龄（未来出生日期）返回 '--' 而非 '-72岁'
- FollowUpTaskList.tsx: DatePicker.RangePicker 添加中文 placeholder

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

crates/erp-health/src/service/patient_service/helper.rs

@@ -56,34 +56,20 @@ pub(crate) fn model_to_resp(m: patient::Model) -> PatientResp {
 /// 详情用 — 解密 Tier 1 字段
 pub(crate) fn model_to_resp_decrypted(crypto: &PiiCrypto, m: patient::Model) -> PatientResp {
     let kek = crypto.kek();
-    let decrypted_id_number = m
-        .id_number
-        .as_ref()
-        .map(|enc| pii::decrypt(kek, enc))
-        .transpose()
-        .ok()
-        .flatten();
-    let decrypted_allergy = m
-        .allergy_history
-        .as_ref()
-        .map(|enc| pii::decrypt(kek, enc))
-        .transpose()
-        .ok()
-        .flatten();
-    let decrypted_medical = m
-        .medical_history_summary
-        .as_ref()
-        .map(|enc| pii::decrypt(kek, enc))
-        .transpose()
-        .ok()
-        .flatten();
-    let decrypted_phone = m
-        .emergency_contact_phone
-        .as_ref()
-        .map(|enc| pii::decrypt(kek, enc))
-        .transpose()
-        .ok()
-        .flatten();
+    let decrypted_id_number = decrypt_field(kek, &m.id_number, "id_number", m.id);
+    let decrypted_allergy = decrypt_field(kek, &m.allergy_history, "allergy_history", m.id);
+    let decrypted_medical = decrypt_field(
+        kek,
+        &m.medical_history_summary,
+        "medical_history_summary",
+        m.id,
+    );
+    let decrypted_phone = decrypt_field(
+        kek,
+        &m.emergency_contact_phone,
+        "emergency_contact_phone",
+        m.id,
+    );
     PatientResp {
         id: m.id,
         user_id: m.user_id,
@@ -105,3 +91,22 @@ pub(crate) fn model_to_resp_decrypted(crypto: &PiiCrypto, m: patient::Model) ->
         version: m.version,
     }
 }
+
+/// 解密单个 PII 字段，失败时输出 warn 日志并返回 None
+fn decrypt_field(
+    kek: &[u8; 32],
+    field: &Option<String>,
+    name: &str,
+    patient_id: Uuid,
+) -> Option<String> {
+    field
+        .as_ref()
+        .map(|enc| pii::decrypt(kek, enc))
+        .transpose()
+        .map_err(|e| {
+            tracing::warn!(patient_id = %patient_id, field = name, error = %e, "PII decrypt failed");
+            e
+        })
+        .ok()
+        .flatten()
+}