feat: support pkg@version format in search

Searching for `esbuild@0.25.12` or `@angular/core@^18` and pressing Enter now navigates directly to
the package version page (or semver filter for ranges) instead of returning no results.

Since in the previous commit I added support for linking to the package page with the a pre-filled
semver version specifier in the query string to populate the version filter, this supports both
exact versions and semver ranges in the search input.

Closes #1416

Author: serhalp

app/pages/search.vue

@@ -441,6 +441,16 @@ function focusElement(el: HTMLElement) {
   el.scrollIntoView({ block: 'nearest', behavior: 'smooth' })
 }
 
+// Parse "pkg@version" from search input (e.g. "esbuild@0.25.12", "@angular/core@^18")
+function parsePackageAtVersion(input: string): { name: string; version?: string } {
+  const atIndex = input.startsWith('@') ? input.indexOf('@', 1) : input.indexOf('@')
+  if (atIndex > 0) {
+    const version = input.slice(atIndex + 1)
+    if (version) return { name: input.slice(0, atIndex), version }
+  }
+  return { name: input }
+}
+
 // Navigate to package page
 async function navigateToPackage(packageName: string) {
   await navigateTo(packageRoute(packageName))
@@ -494,6 +504,12 @@ function handleResultsKeydown(e: KeyboardEvent) {
     const inputValue = (document.activeElement as HTMLInputElement).value.trim()
     if (!inputValue) return
 
+    // Handle "pkg@version" format (e.g. "esbuild@0.25.12", "@angular/core@^18")
+    const { name, version } = parsePackageAtVersion(inputValue)
+    if (version) {
+      return navigateTo(packageRoute(name, version))
+    }
+
     // When instantSearch is off, commit the query so search starts
     committedQuery.value = inputValue