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/navbar/index.js

@@ -0,0 +1,27 @@
+const app = getApp();
+
+Component({
+  properties: {
+    title: { type: String, value: '' },
+    showBack: { type: Boolean, value: false }
+  },
+  data: {
+    statusBarHeight: 20
+  },
+  lifetimes: {
+    attached() {
+      const h = (app.globalData && app.globalData.statusBarHeight) || 20;
+      this.setData({ statusBarHeight: h });
+    }
+  },
+  methods: {
+    onBack() {
+      const pages = getCurrentPages();
+      if (pages.length > 1) {
+        wx.navigateBack();
+      } else {
+        wx.reLaunch({ url: '/pages/index/index' });
+      }
+    }
+  }
+});