fix(pl): 计划详情用关联证件附件替换危化品证书区。

Web 与 H5 详情将关联购买证/运输证移到装送货后并以附件卡片展示；用证接口回填证件附件 URL。

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/tests/test_pl_quota_sources.py

@@ -317,3 +317,39 @@ def test_missing_contract_is_empty_binding_not_unreadable(case, contract_id):
     assert rows[0]['bindingsReadable'] is True
     assert rows[0]['certificates'] == []
     assert rows[1]['bindingsReadable'] is False
+
+
+def test_plan_quota_usages_include_cert_attachment_urls(case):
+    from app.models.crm_models import CrmContract
+    from app.models.pl_quota_models import (
+        PlPlanCertUsage, PlPlanCertUsageItem, PlPurchaseCert, PlTransportCert,
+    )
+    from app.services.pl_quota_planning import get_plan_quota
+    c = case
+    for model in (CrmContract, PlPlanCertUsage, PlPlanCertUsageItem, PlPurchaseCert, PlTransportCert):
+        model.__table__.create(c.db.bind)
+    c.db.add(PlPurchaseCert(
+        id='p1', cert_no='G-BUY', product_name_on_cert='硫酸', valid_use_text='一次有效',
+        buyer_name='买方', seller_name='卖方', total_qty=33, quantity_unit='吨',
+        attachment_urls='https://example.com/buy.jpg', tenant_no='t', status='active',
+    ))
+    c.db.add(PlTransportCert(
+        id='t1', cert_no='Y-TR', product_name_on_cert='硫酸', valid_use_text='多次有效',
+        shipper_name='货主', total_qty=70, quantity_unit='吨', vehicle_numbers_json=['皖A1'],
+        attachment_urls='', tenant_no='t', status='active',
+    ))
+    c.db.add(PlPlanCertUsage(
+        id='u1', tenant_no='t', plan_id='plan', plan_no_snapshot='PLAN',
+        cert_type='purchase', cert_id='p1', cert_no_snapshot='G-BUY', cert_revision=1,
+        quantity_unit='吨', reserved_qty=10, used_qty=0, usage_status='reserved',
+    ))
+    c.db.add(PlPlanCertUsage(
+        id='u2', tenant_no='t', plan_id='plan', plan_no_snapshot='PLAN',
+        cert_type='transport', cert_id='t1', cert_no_snapshot='Y-TR', cert_revision=1,
+        quantity_unit='吨', reserved_qty=10, used_qty=0, usage_status='reserved',
+    ))
+    c.db.flush()
+    usages = {u['certId']: u for u in get_plan_quota(c.db, c.user, 'plan')['usages']}
+    assert usages['p1']['attachmentUrls'] == 'https://example.com/buy.jpg'
+    assert usages['p1']['certNo'] == 'G-BUY'
+    assert usages['t1']['attachmentUrls'] in ('', None)