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/chip/index.wxml

@@ -0,0 +1,6 @@
+<view
+  class="chip {{active ? 'chip--active' : ''}}"
+  style="{{color ? 'border-color:' + color + '66; color:' + color : ''}}"
+  bindtap="onTap">
+  <text>{{label}}</text>
+</view>