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/pages/detail/detail.wxss

@@ -0,0 +1,57 @@
+.page { min-height: 100vh; background: var(--bg-grad); padding-bottom: 180rpx; }
+.hero { width: 100%; height: 520rpx; background: var(--surface-2); }
+.hero__img { width: 100%; height: 100%; display: block; }
+.hero__ph { width: 100%; height: 100%; display: flex; align-items: center; justify-content: center; font-size: 120rpx; }
+
+.name { font-size: 48rpx; font-weight: 700; color: var(--text); letter-spacing: 1rpx; }
+
+.metas { display: flex; flex-wrap: wrap; gap: 14rpx; margin-top: 24rpx; }
+.meta {
+  background: var(--surface); border: 1rpx solid var(--line);
+  border-radius: var(--radius-sm); padding: 16rpx 22rpx;
+  min-width: calc((100% - 42rpx) / 4);
+}
+.meta__k { font-size: 20rpx; color: var(--text-3); }
+.meta__v { font-size: 26rpx; color: var(--text); margin-top: 6rpx; font-weight: 600; }
+
+.block { margin-top: 36rpx; }
+.block__h { margin-bottom: 16rpx; }
+.chips { display: flex; flex-wrap: wrap; gap: 12rpx; }
+
+.steps { display: flex; flex-direction: column; gap: 18rpx; }
+.step { display: flex; gap: 20rpx; align-items: flex-start; }
+.step__n {
+  flex: 0 0 auto; width: 48rpx; height: 48rpx; border-radius: 999rpx;
+  background: var(--gold-soft); color: var(--gold); border: 1rpx solid var(--gold-line);
+  display: flex; align-items: center; justify-content: center; font-weight: 700; font-size: 26rpx;
+}
+.step__t { flex: 1; font-size: 28rpx; color: var(--text); line-height: 1.5; padding-top: 6rpx; }
+
+.tips {
+  font-size: 28rpx; color: var(--text-2); line-height: 1.6;
+  background: var(--surface); border: 1rpx solid var(--line);
+  border-radius: var(--radius-sm); padding: 24rpx;
+}
+
+.hscroll { white-space: nowrap; margin-top: 12rpx; }
+.hscroll__item { display: inline-block; width: 300rpx; margin-right: 20rpx; vertical-align: top; }
+
+.addbar {
+  position: fixed; left: 0; right: 0; bottom: 0;
+  padding: 20rpx 32rpx;
+  background: rgba(14,17,16,0.92);
+  backdrop-filter: blur(12px);
+  border-top: 1rpx solid var(--line);
+  padding-bottom: calc(20rpx + env(safe-area-inset-bottom));
+}
+.cta {
+  display: flex; align-items: center; justify-content: center;
+  background: linear-gradient(135deg, var(--gold) 0%, var(--gold-2) 100%);
+  color: #0E1110; font-weight: 700; font-size: 32rpx;
+  border-radius: 999rpx; padding: 26rpx;
+}
+
+.empty-page { min-height: 100vh; background: var(--bg-grad); }
+.topbar { height: 88rpx; display: flex; align-items: center; padding: 0 24rpx; }
+.topbar__back { font-size: 56rpx; color: var(--gold); width: 60rpx; line-height: 1; }
+.empty { color: var(--text-3); font-size: 28rpx; text-align: center; padding: 120rpx 0; }