feat: transport incidents with truck number support

- DB: trucks table + incidents.truck_id FK + transport enum value
- Validation: transport type requires truck_id
- Create API: validates truck exists/active, persists truck_id
- Report form: truck dropdown shown when type=transport (required)
- Admin: TruckManager CRUD + /api/admin/trucks route
- Detail: trucks join surfaced in incident-detail + detail page query
- Inbox (HSE + supervisor): truck filter, transport in TYPE_OPTIONS,
  fixed stale enum values (dropped dangerous_occurrence/mhe_asset/occupational_disease)
- List: transport label + truck number badge in rows
- i18n: transport + truckLabel/truckPlaceholder in en/ms/zh

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CPf5Rc8QPx6V8KLEEgfKEQ

messages/zh.json

@@ -16,7 +16,9 @@
     "qualityScoreLabel": "报告质量 — {score}/10",
     "errorGeneric": "出现错误，请重试。",
     "savedOffline": "报告已保存。当您重新联网时将自动提交。",
-    "offlineBanner": "您处于离线状态。您的报告将在重新联网时自动提交。"
+    "offlineBanner": "您处于离线状态。您的报告将在重新联网时自动提交。",
+    "truckLabel": "货车",
+    "truckPlaceholder": "选择货车…"
   },
   "IncidentType": {
     "injury": "受伤/医疗",
@@ -25,7 +27,8 @@
     "asset_damage": "资产/设备损坏",
     "environmental": "环境事故",
     "security": "安全事故",
-    "fire": "火灾/紧急情况"
+    "fire": "火灾/紧急情况",
+    "transport": "运输 / 车辆"
   },
   "MedicalStatus": {
     "none": "无需治疗",