fix(discover): filter chips use applied state and apply immediately on top-chip tap

- Top chip '推荐' now active only when no active filter (was hardcoded)
- Top chip '丹阳本地' uses applied.region (was tempRegion)
- Top chip '年龄' uses applied age range
- New onTopRegionTap applies region filter immediately and refreshes results
- Panel onRegionTap preserved for filter-panel multi-select flow

miniapp/pages/discover/discover.ts

@@ -134,6 +134,19 @@ Page({
     this.setData({ tempRegion: this.data.tempRegion === val ? '' : val });
   },
 
+  /** 顶部"丹阳本地" chip 专用：立即应用 region 筛选并刷新结果 */
+  onTopRegionTap(e: WechatMiniprogram.TouchEvent) {
+    const val = (e.currentTarget.dataset as any).val as string;
+    const nextRegion = this.data.applied.region === val ? '' : val;
+    const applied = { ...this.data.applied, region: nextRegion };
+    this.setData({
+      tempRegion: nextRegion,
+      applied,
+      hasActiveFilter: this._hasActiveFilter(applied),
+    });
+    this.fetchDiscover(true);
+  },
+
   onMinAgeChange(e: any) {
     let min = Number((e as any).detail.value);
     if (min > this.data.tempAgeMax) min = this.data.tempAgeMax;