fix(mobile): replace App-Plus unsupported date and query APIs

`URLSearchParams` is absent from the App-Plus JS core, and
`toLocaleDateString('sv-SE', { timeZone: 'Asia/Shanghai' })` depends on full
ICU data that the App runtime does not ship, so the work-result pages built
either a broken query string or the device-local date.

Build query strings with `encodeURIComponent`, and centralise the business day
in `currentShanghaiDate()`, which shifts the epoch by a fixed UTC+8 offset
before slicing the ISO date. Asia/Shanghai has no DST, so the fixed offset is
exact rather than an approximation.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

mobile-uni/src/pages/supervisor/work-results/index.vue

@@ -55,6 +55,7 @@ import { fetchMobileIdentity } from '@/services/position';
 import { updateAssistantCaptureStatus } from '@/services/personal-assistant';
 import { openProtectedSource } from '@/services/source-preview';
 import { getProjectWorkResult } from '@/services/work-results';
+import { currentShanghaiDate } from '@/utils/date';
 import SupervisorTabBar from '@/components/SupervisorTabBar.vue';
 import WorkDateSelector from '@/components/WorkDateSelector.vue';
 
@@ -62,8 +63,7 @@ const result = ref<ProjectWorkResult | null>(null);
 const currentProject = ref<MobileProject | null>(getCurrentProject());
 const message = ref('');
 const loading = ref(false);
-const currentDate = () => new Date().toLocaleDateString('sv-SE', { timeZone: 'Asia/Shanghai' });
-const today = ref(currentDate());
+const today = ref(currentShanghaiDate());
 const workDate = ref(today.value);
 const pageNum = ref(1);
 const pageSize = 20;
@@ -116,7 +116,7 @@ const openSource = (item: WorkResultItem) => openProtectedSource(item.sourceUrl,
 const sourceLabel = (value: string) => ({ TEXT: '文字来源', VOICE: '原始语音', IMAGE: '现场照片', VIDEO: '现场视频' }[value] || '原始来源');
 const goBack = () => uni.navigateBack({ fail: () => uni.redirectTo({ url: '/pages/supervisor/index/index' }) });
 onShow(() => {
-  today.value = currentDate();
+  today.value = currentShanghaiDate();
   load();
 });
 </script>