feat: init fitness-coach (backend + miniprogram)

- backend: NestJS service with exercise/plan data
- miniprogram: WeChat mini program client
- exclude node_modules, dist, runtime data-store, local env

miniprogram/components/exercise-card/index.wxss

@@ -0,0 +1,40 @@
+.ex-card {
+  background: var(--surface);
+  border-radius: var(--radius-sm);
+  overflow: hidden;
+  border: 1rpx solid var(--line);
+  width: 100%;
+}
+.ex-card__media {
+  position: relative;
+  width: 100%;
+  height: 200rpx;
+  background: var(--surface-2);
+}
+.ex-card--compact .ex-card__media { height: 160rpx; }
+.ex-card__img { width: 100%; height: 100%; display: block; }
+.ex-card__ph {
+  width: 100%; height: 100%;
+  display: flex; align-items: center; justify-content: center;
+  font-size: 64rpx;
+}
+.ex-card__type {
+  position: absolute; left: 12rpx; top: 12rpx;
+  font-size: 20rpx; color: var(--text-2);
+  background: rgba(0,0,0,0.45); padding: 4rpx 14rpx; border-radius: 999rpx;
+}
+.ex-card__score {
+  position: absolute; right: 12rpx; top: 12rpx;
+  font-size: 20rpx; color: #0E1110; font-weight: 700;
+  background: var(--gold); padding: 4rpx 14rpx; border-radius: 999rpx;
+}
+.ex-card__body { padding: 16rpx 18rpx 20rpx; }
+.ex-card__name {
+  font-size: 28rpx; font-weight: 600; color: var(--text);
+  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
+}
+.ex-card__chips { display: flex; gap: 10rpx; margin-top: 12rpx; flex-wrap: wrap; }
+.ex-card__reason {
+  margin-top: 12rpx; font-size: 22rpx; color: var(--text-3);
+  line-height: 1.45;
+}