fix(web-ui): remove client-side onKeyDown from server component to fix 500 on /docs

The search input's onKeyDown handler used window.location.href which is
unavailable during SSR, causing the /docs page to crash. Replaced with
a Link wrapper so it's fully server-rendered.

apps/web/app/docs/page.tsx

@@ -53,9 +53,13 @@ export default async function DocsIndexPage() {
         </p>
 
         {/* Search bar */}
-        <div className="mt-8 relative max-w-2xl">
+        <div className="mt-8">
+          <Link
+            href="/search"
+            className="relative flex items-center max-w-2xl group"
+          >
             <svg
-            className="absolute left-3 top-1/2 -translate-y-1/2 w-5 h-5 text-[#62666d]"
+              className="absolute left-3 top-1/2 -translate-y-1/2 w-5 h-5 text-[#62666d] group-focus-within:text-[#5e6ad2] transition-colors"
               fill="none"
               stroke="currentColor"
               viewBox="0 0 24 24"
@@ -67,20 +71,10 @@ export default async function DocsIndexPage() {
                 d="M21 21l-6-6m2-5a7 7 0 11-14 0 7 7 0 0114 0z"
               />
             </svg>
-          <input
+            <span className="w-full pl-10 pr-4 py-3 bg-[#191a1b] border border-[#1f2022] rounded-lg text-[#62666d] group-hover:border-[#5e6ad2]/40 transition-colors">
-            type="text"
+              Search documents, tags, authors...
-            placeholder="Search documents, tags, authors..."
+            </span>
-            readOnly
+          </Link>
-            className="w-full pl-10 pr-4 py-3 bg-[#191a1b] border border-[#1f2022] rounded-lg text-[#e2e4e7] placeholder-[#62666d] focus:outline-none focus:border-[#5e6ad2] focus:ring-1 focus:ring-[#5e6ad2]/30 transition-colors"
-            onKeyDown={(e) => {
-              if (e.key === "Enter" && e.currentTarget.value) {
-                window.location.href = `/search?q=${encodeURIComponent(e.currentTarget.value)}`;
-              }
-            }}
-          />
-          <kbd className="absolute right-3 top-1/2 -translate-y-1/2 text-xs text-[#62666d] bg-[#0f1011] border border-[#1f2022] rounded px-1.5 py-0.5">
-            ↵
-          </kbd>
         </div>
 
         {/* Recent strip */}