chore: commit pending ZXDB explorer changes prior to index perf work

Context
- Housekeeping commit to capture all current ZXDB Explorer work before index-page performance optimizations.

Includes
- Server-rendered entry detail page with ISR and parallelized DB queries.
- Node runtime for ZXDB API routes and params validation updates for Next 15.
- ZXDB repository extensions (facets, label queries, category queries).
- Cross-linking and Link-based prefetch across ZXDB UI.
- Cache headers on low-churn list APIs.

Notes
- Follow-up commit will focus specifically on speeding up index pages via SSR initial data and ISR.

Signed-off-by: Junie@lucy.xalior.com

src/app/zxdb/languages/LanguageList.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import { useEffect, useState } from "react";
+import Link from "next/link";
 
 type Language = { id: string; name: string };
 
@@ -27,7 +28,7 @@ export default function LanguageList() {
       <ul className="list-group">
         {items.map((l) => (
           <li key={l.id} className="list-group-item d-flex justify-content-between align-items-center">
-            <a href={`/zxdb/languages/${l.id}`}>{l.name}</a>
+            <Link href={`/zxdb/languages/${l.id}`}>{l.name}</Link>
             <span className="badge text-bg-light">{l.id}</span>
           </li>
         ))}