style: format web/src with oxfmt defaults (via vp fmt)

One-time mechanical sweep, isolated from any functional change.
- oxfmt defaults: double quotes, semicolons, 2-space indent, LF,
  printWidth 100, trailing commas, bracket spacing, arrow parens.
- vite.config.ts gains an fmt.ignorePatterns block for web/static:
  vendored/minified assets (htmx.min.js, compiled css) must never
  be reformatted.
- Verified: rebuild after the sweep produces byte-identical JS/CSS
  bundles; only sourcemaps changed (they embed sourcesContent).

web/src/header.ts

@@ -21,11 +21,7 @@ const restoreLibrarySelection = (): void => {
   const savedLibrary = getSelectedLibrary();
   if (!savedLibrary) return;
 
-  const dropdownSelectors = [
-    "#library-select",
-    "#selected-library",
-    "#library_id",
-  ];
+  const dropdownSelectors = ["#library-select", "#selected-library", "#library_id"];
 
   for (const selector of dropdownSelectors) {
     const dropdown = document.querySelector(selector) as HTMLSelectElement;