fix: address some a11y issues

Author: danielroe

app/components/CodeFileTree.vue

@@ -53,6 +53,7 @@ function isExpanded(path: string): boolean {
       <!-- Directory -->
       <template v-if="node.type === 'directory'">
         <button
+          type="button"
           class="w-full flex items-center gap-1.5 py-1.5 px-3 text-left font-mono text-sm transition-colors hover:bg-bg-muted"
           :class="isNodeActive(node) ? 'text-fg' : 'text-fg-muted'"
           :style="{ paddingLeft: `${depth * 12 + 12}px` }"

app/components/CodeMobileTreeDrawer.vue

@@ -36,6 +36,7 @@ onUnmounted(() => {
 <template>
   <!-- Toggle button (mobile only) -->
   <button
+    type="button"
     class="md:hidden fixed bottom-4 right-4 z-40 w-12 h-12 bg-bg-elevated border border-border rounded-full shadow-lg flex items-center justify-center text-fg-muted hover:text-fg transition-colors"
     aria-label="Toggle file tree"
     @click="isOpen = !isOpen"
@@ -73,6 +74,7 @@ onUnmounted(() => {
       >
         <span class="font-mono text-sm text-fg-muted">Files</span>
         <button
+          type="button"
           class="text-fg-muted hover:text-fg transition-colors"
           aria-label="Close file tree"
           @click="isOpen = false"

app/pages/code/[...path].vue

@@ -312,7 +312,9 @@ useSeoMeta({
           </NuxtLink>
           <!-- Version selector -->
           <div v-if="version && availableVersions.length > 0" class="relative shrink-0">
+            <label for="version-select" class="sr-only">Select version</label>
             <select
+              id="version-select"
               :value="version"
               :title="`v${version}`"
               class="appearance-none pl-2 pr-6 py-0.5 font-mono text-sm bg-bg-muted border border-border rounded cursor-pointer hover:border-border-hover transition-colors max-w-32 sm:max-w-48 truncate"
@@ -414,6 +416,7 @@ useSeoMeta({
             <div class="flex items-center gap-2">
               <button
                 v-if="selectedLines"
+                type="button"
                 class="px-2 py-1 font-mono text-xs text-fg-muted bg-bg-subtle border border-border rounded hover:text-fg hover:border-border-hover transition-colors"
                 @click="copyPermalink"
               >