feat: 添加论坛首页相关资源文件和基础功能

新增论坛首页所需的图片资源、CSS样式文件、Vue组件和基础功能实现。包括：
1. 添加多个图标图片资源
2. 创建index.css和sectionIndex.css样式文件
3. 实现论坛首页的Vue组件结构和基础交互
4. 添加论坛板块列表和帖子展示功能
5. 实现公共样式和布局组件

img/collect-golden.svg

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+<?xml version="1.0" encoding="utf-8"?>
+<svg version="1.1" xmlns:xlink="http://www.w3.org/1999/xlink" width="20px" height="19px" xmlns="http://www.w3.org/2000/svg">
+  <g transform="matrix(1 0 0 1 -366 -5694 )">
+    <path d="M 19.3269230769231 6.8122243226213  C 19.775641025641 6.88405797101449  20 7.06763285024155  20 7.36294896030246  C 20 7.53854232304138  19.8958333333333 7.73009871875656  19.6875 7.93761814744802  L 15.3245192307692 12.1758034026465  L 16.3581730769231 18.1619407687461  C 16.3661858974359 18.217811384163  16.3701923076923 18.2976265490443  16.3701923076923 18.40138626339  C 16.3701923076923 18.5689981096408  16.328125 18.7106700273052  16.2439903846154 18.8264020163831  C 16.1598557692308 18.942134005461  16.0376602564103 19  15.8774038461538 19  C 15.7251602564103 19  15.5649038461538 18.9521109010712  15.3966346153846 18.8563327032136  L 10 16.0308758664146  L 4.60336538461538 18.8563327032136  C 4.42708333333333 18.9521109010712  4.26682692307692 19  4.12259615384615 19  C 3.95432692307692 19  3.828125 18.942134005461  3.74399038461538 18.8264020163831  C 3.65985576923077 18.7106700273052  3.61778846153846 18.5689981096408  3.61778846153846 18.40138626339  C 3.61778846153846 18.3534971644612  3.62580128205128 18.2736819995799  3.64182692307692 18.1619407687461  L 4.67548076923077 12.1758034026465  L 0.300480769230769 7.93761814744802  C 0.100160256410256 7.72211720226843  0 7.53056080655325  0 7.36294896030246  C 0 7.06763285024155  0.224358974358974 6.88405797101449  0.673076923076923 6.8122243226213  L 6.70673076923077 5.93824826717076  L 9.41105769230769 0.490863264020163  C 9.56330128205128 0.16362108800672  9.75961538461539 0  10 0  C 10.2403846153846 0  10.4366987179487 0.16362108800672  10.5889423076923 0.490863264020163  L 13.2932692307692 5.93824826717076  L 19.3269230769231 6.8122243226213  Z " fill-rule="nonzero" fill="#f3974b" stroke="none" transform="matrix(1 0 0 1 366 5694 )" />
+  </g>
+</svg>

img/sections-left.svg

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<svg version="1.1" xmlns:xlink="http://www.w3.org/1999/xlink" width="60px" height="240px" xmlns="http://www.w3.org/2000/svg">
+  <g transform="matrix(1 0 0 1 -360 -1036 )">
+    <path d="M 10 1  L 58.3017434089711 1  C 34.1415425553555 34.0611806206907  20 75.1021981437059  20 120  C 20 165.351835775029  34.4290045215671 206.768488498722  59.0387603330385 240  L 10 240  C 4.39999999999998 240  0 235.618257261411  0 230.041493775934  L 0 10.954356846473  C 0 5.37759336099589  4.39999999999998 0.995850622406579  10 1  Z " fill-rule="nonzero" fill="#50e3c2" stroke="none" transform="matrix(1 0 0 1 360 1036 )" />
+  </g>
+</svg>