feat: migrate from Create React App to Vite

Rebuild the site on the stack the other converted sites share: Vite 8,
React 19, TypeScript 7, react-router 8, Biome and sanitize.css, with the
site data moved out of the bundle into static-contents/.

- base the database code on cerebellum.neuroinf.jp and keep the pupil
  platform's table layout, about page and menu
- load the Flickr badge feed as JSONP without extra libraries
- serve the XooNIps data from modules/xoonips/, redirecting the old
  download and /database/file URLs
- restate the column widths as border-box totals and keep form controls
  on white
- track page views with GA4

src/common/Header.module.css

@@ -1,16 +1,16 @@
 .header {
-        padding-bottom: 15px;
-        background: url(./assets/images/theme/header_bar.jpg) bottom left repeat-x;
+    padding-bottom: 15px;
+    background: url(./assets/images/theme/header_bar.jpg) bottom left repeat-x;
 }
 
 .h1 {
-        min-width: 900px;
-        height: 116px;
-        background: url(./assets/images/theme/pupil_photo.jpg) top right no-repeat;
-        margin: 0;
+    min-width: 900px;
+    height: 116px;
+    background: url(./assets/images/theme/pupil_photo.jpg) top right no-repeat;
+    margin: 0;
 }
 
 .img {
-        width: 580px;
-        height: 116px;
-}
+    width: 580px;
+    height: 116px;
+}