feat(miniprogram): 适老化修复 — Phase 2e

M6: 创建 utils/date.ts 统一日期工具函数（formatDate/formatDateTime/toRelativeDate 等）
M8: 28 个 SCSS 文件 font-size 20px → 22px 全量适老化
M7: request.ts 增加 403 权限不足/5xx 服务器错误/网络超时异常统一拦截

apps/miniprogram/src/utils/date.ts

@@ -0,0 +1,74 @@
+/**
+ * 统一日期工具函数 — 替代分散在各页面的内联日期格式化
+ */
+
+/** 格式化为 YYYY-MM-DD */
+export function formatDate(iso: string | null | undefined): string {
+  if (!iso) return '-';
+  const d = new Date(iso);
+  if (isNaN(d.getTime())) return '-';
+  const y = d.getFullYear();
+  const m = String(d.getMonth() + 1).padStart(2, '0');
+  const day = String(d.getDate()).padStart(2, '0');
+  return `${y}-${m}-${day}`;
+}
+
+/** 格式化为 YYYY-MM-DD HH:mm */
+export function formatDateTime(iso: string | null | undefined): string {
+  if (!iso) return '-';
+  const d = new Date(iso);
+  if (isNaN(d.getTime())) return '-';
+  const date = formatDate(iso);
+  const h = String(d.getHours()).padStart(2, '0');
+  const min = String(d.getMinutes()).padStart(2, '0');
+  return `${date} ${h}:${min}`;
+}
+
+/** 格式化为 YYYY-MM-DD HH:mm:ss */
+export function formatDateTimeFull(iso: string | null | undefined): string {
+  if (!iso) return '-';
+  const d = new Date(iso);
+  if (isNaN(d.getTime())) return '-';
+  const base = formatDateTime(iso);
+  const s = String(d.getSeconds()).padStart(2, '0');
+  return `${base}:${s}`;
+}
+
+/** 获取今天的 YYYY-MM-DD */
+export function today(): string {
+  const d = new Date();
+  const y = d.getFullYear();
+  const m = String(d.getMonth() + 1).padStart(2, '0');
+  const day = String(d.getDate()).padStart(2, '0');
+  return `${y}-${m}-${day}`;
+}
+
+/** 相对时间：今天/昨天/前天/更早 */
+export function toRelativeDate(iso: string | null | undefined): string {
+  if (!iso) return '-';
+  const d = new Date(iso);
+  if (isNaN(d.getTime())) return '-';
+
+  const now = new Date();
+  const todayStart = new Date(now.getFullYear(), now.getMonth(), now.getDate());
+  const targetStart = new Date(d.getFullYear(), d.getMonth(), d.getDate());
+  const diffDays = Math.round((todayStart.getTime() - targetStart.getTime()) / 86400000);
+
+  if (diffDays === 0) return '今天';
+  if (diffDays === 1) return '昨天';
+  if (diffDays === 2) return '前天';
+  return formatDate(iso);
+}
+
+/** 格式化为中文月日 + 星期 */
+export function formatMonthDayWeek(iso: string | null | undefined): string {
+  if (!iso) return '';
+  const d = new Date(iso);
+  if (isNaN(d.getTime())) return '';
+
+  const weekdays = ['日', '一', '二', '三', '四', '五', '六'];
+  const m = d.getMonth() + 1;
+  const day = d.getDate();
+  const w = weekdays[d.getDay()];
+  return `${m}月${day}日 周${w}`;
+}