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 and forum code on cerebellum.neuroinf.jp, keeping
  the CBSN item fields for papers, books and presentations
- serve the XooNIps and forum data from modules/, redirecting the old
  download and /database/file URLs
- restate the theme sizes as border-box totals and keep form controls
  on white
- track page views with GA4

src/database/blocks/IndexTree.module.css

@@ -4,8 +4,10 @@
     border-bottom: 1px solid #404040;
     border-right: 1px solid #404040;
     background-color: white;
-    height: 400px;
-    width: calc(100% - 6px);
+    /* border-box totals: 400 + 3px padding + 1px border per side, and a width
+       that keeps the 2px the original content-box rule overflowed by. */
+    height: 408px;
+    width: calc(100% + 2px);
     overflow: auto;
     margin: 0 auto;
     padding: 3px;
@@ -14,6 +16,8 @@
 
 .formButton {
     margin: 3px 3px 10px;
+    /* sanitize.css forms.css leaves buttons transparent */
+    background-color: #ffffff;
 }
 
 .indexTree div span {
@@ -44,7 +48,9 @@
 .indexTree:global(.rc-tree .rc-tree-treenode .rc-tree-indent .rc-tree-indent-unit:not(:last-child)) {
     background-position: -9px 0;
 }
-.indexTree:global(.rc-tree .rc-tree-treenode .rc-tree-indent .rc-tree-indent-unit:not(:last-child).rc-tree-indent-unit-end) {
+.indexTree:global(
+    .rc-tree .rc-tree-treenode .rc-tree-indent .rc-tree-indent-unit:not(:last-child).rc-tree-indent-unit-end
+) {
     background-position: -18px 0;
 }
 .indexTree:global(.rc-tree .rc-tree-treenode .rc-tree-indent .rc-tree-indent-unit:last-child.rc-tree-indent-unit-end) {
@@ -88,4 +94,4 @@
 .indexTree:global(.rc-tree .rc-tree-treenode .rc-tree-node-content-wrapper .rc-tree-title) {
     vertical-align: middle;
     line-height: 20px;
-}
+}