feat: 将应用图标从SVG格式更换为JPG格式

- 在app-instance前端应用中将logo图标从/boardware-logo.svg替换为/boardware-logo.jpg
- 在auth-portal认证门户中将logo图标从/boardware-logo.svg替换为/boardware-logo.jpg
- 更新了layout.tsx、Header.tsx以及登录注册页面中的图标引用
- 删除了原有的SVG格式logo文件

app-instance/frontend/public/boardware-logo.svg

@@ -1,67 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 320" role="img" aria-labelledby="title desc">
-  <title id="title">BoardWare logo</title>
-  <desc id="desc">A triangular BoardWare mark in blue and red with the word BoardWare above it.</desc>
-  <defs>
-    <linearGradient id="blueTop" x1="0%" y1="0%" x2="0%" y2="100%">
-      <stop offset="0%" stop-color="#142f58" />
-      <stop offset="100%" stop-color="#163a70" />
-    </linearGradient>
-    <linearGradient id="blueMid" x1="0%" y1="0%" x2="0%" y2="100%">
-      <stop offset="0%" stop-color="#2c5f9f" />
-      <stop offset="100%" stop-color="#4c89d0" />
-    </linearGradient>
-    <linearGradient id="blueBottom" x1="0%" y1="0%" x2="0%" y2="100%">
-      <stop offset="0%" stop-color="#5d95da" />
-      <stop offset="100%" stop-color="#2f63af" />
-    </linearGradient>
-    <linearGradient id="redTop" x1="0%" y1="0%" x2="0%" y2="100%">
-      <stop offset="0%" stop-color="#421216" />
-      <stop offset="100%" stop-color="#70161d" />
-    </linearGradient>
-    <linearGradient id="redMid" x1="0%" y1="0%" x2="0%" y2="100%">
-      <stop offset="0%" stop-color="#7a161c" />
-      <stop offset="100%" stop-color="#932127" />
-    </linearGradient>
-    <linearGradient id="redBottom" x1="0%" y1="0%" x2="0%" y2="100%">
-      <stop offset="0%" stop-color="#8a1f23" />
-      <stop offset="100%" stop-color="#631116" />
-    </linearGradient>
-  </defs>
-
-  <text
-    x="26"
-    y="46"
-    transform="rotate(10 26 46)"
-    fill="#2a3a55"
-    font-family="Georgia, Times New Roman, serif"
-    font-size="24"
-    font-style="italic"
-    font-weight="600"
-    letter-spacing="0.5"
-  >
-    BoardWare
-  </text>
-
-  <polygon points="20,58 67,64 47,126" fill="url(#blueTop)" />
-  <polygon points="74,65 120,71 101,133" fill="url(#blueTop)" />
-  <polygon points="127,71 172,77 154,138" fill="url(#blueTop)" />
-  <polygon points="180,78 224,84 206,145" fill="url(#blueTop)" />
-
-  <polygon points="50,135 88,141 72,191" fill="url(#blueMid)" />
-  <polygon points="123,144 160,149 143,199" fill="url(#blueMid)" />
-  <polygon points="85,211 122,216 105,268" fill="url(#blueMid)" />
-  <polygon points="139,219 176,224 159,276" fill="url(#blueBottom)" />
-  <polygon points="170,224 209,229 191,283" fill="url(#blueBottom)" />
-  <polygon points="138,283 191,283 165,320" fill="url(#blueBottom)" />
-
-  <polygon points="224,84 246,90 210,148" fill="url(#redTop)" />
-  <polygon points="249,91 270,97 230,154" fill="url(#redTop)" />
-  <polygon points="273,98 294,104 249,161" fill="url(#redTop)" />
-  <polygon points="297,105 314,111 267,168" fill="url(#redTop)" />
-
-  <polygon points="211,148 230,154 203,207" fill="url(#redMid)" />
-  <polygon points="233,155 251,160 220,213" fill="url(#redMid)" />
-  <polygon points="204,207 221,213 194,265" fill="url(#redBottom)" />
-  <polygon points="223,214 240,219 208,270" fill="url(#redBottom)" />
-  <polygon points="191,283 208,270 165,320" fill="url(#redBottom)" />
-</svg>