feat: add new components and update UI and type declarations

- add AiTabSwitch component with its image assets and styles
- add Welcome component for welcome text, weather display and notice messages
- update ChatMainList to use new components and add background header layout
- replace custom swiper in NoticeMessage with Vant VanSwipe component
- add Vant Swipe type definitions to components.d.ts

src/pages/home/components/AiTabSwitch/index.vue

@@ -0,0 +1,57 @@
+<template>
+  <div class="w-full">
+    <div class="relative w-full h-[50px] flex overflow-hidden">
+      <div class="tab-item is-left" :class="{ active: modelValue === 0 }" @tap="handleSwitch(0)">
+        <div class="tab-content">
+          <img v-if="leftSelected || leftUnselected" :src="modelValue === 0
+            ? leftSelected || leftUnselected
+            : leftUnselected || leftSelected
+            " class="tab-image" mode="scaleToFill" />
+          <div class="tab-label">
+            <span class="tab-text">探索发现</span>
+          </div>
+        </div>
+      </div>
+
+      <div class="tab-item is-right" :class="{ active: modelValue === 1 }" @tap="handleSwitch(1)">
+        <div class="tab-content">
+          <img v-if="rightSelected || rightUnselected" :src="modelValue === 1
+            ? rightSelected || rightUnselected
+            : rightUnselected || rightSelected
+            " class="tab-image" mode="scaleToFill" />
+          <div class="tab-label">
+            <span class="tab-text">AI伴游</span>
+            <div v-if="showDot" :class="[
+              'status-dot',
+              modelValue === 1
+                ? 'status-dot--active'
+                : 'status-dot--inactive',
+            ]"></div>
+          </div>
+        </div>
+      </div>
+    </div>
+  </div>
+</template>
+
+<script setup>
+import leftSelected from "./images/L_02.png";
+import leftUnselected from "./images/L_01.png";
+import rightSelected from "./images/R_02.png";
+import rightUnselected from "./images/R_01.png";
+
+const props = defineProps({
+  modelValue: { type: Number, default: 0 },
+  showDot: { type: Boolean, default: true },
+});
+const emit = defineEmits(["update:modelValue", "change"]);
+
+const handleSwitch = (i) => {
+  emit("update:modelValue", i);
+  emit("change", i);
+};
+</script>
+
+<style lang="scss" scoped>
+@import "./styles/index.scss";
+</style>