perf(zxdb): server-render index pages with ISR and initial data

Why
- Reduce time-to-first-content on ZXDB index pages by eliminating the initial client-side fetch and enabling incremental static regeneration.

What
- Main Explorer (/zxdb):
  - Server-renders first page of results and lookup lists (genres, languages, machinetypes) and passes them as initial props.
  - Keeps client interactivity for subsequent searches/filters.
- Labels index (/zxdb/labels):
  - Server-renders first page of empty search and passes as initial props to skip the first fetch.
- Category lists:
  - Genres (/zxdb/genres), Languages (/zxdb/languages), Machine Types (/zxdb/machinetypes) now server-render their lists and export revalidate=3600.
  - Refactored list components to accept server-provided items; removed on-mount fetching.
- Links & prefetch:
  - Replaced remaining anchors with Next Link to enable prefetch where applicable.

Tech details
- Added revalidate=3600 to the index pages for ISR.
- Updated ZxdbExplorer to accept initial results and initial filter lists; skips first client fetch when initial props are present.
- Updated LabelsSearch to accept initial payload and skip first fetch in default state.
- Updated GenreList, LanguageList, MachineTypeList to be presentational components receiving items from server pages.

Notes
- Low-churn list APIs already emit Cache-Control for CDN; list pages now render instantly from server.
- Further polish (breadcrumbs, facet counts UI) can build on this foundation without reintroducing initial network waits.

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

COMMIT_EDITMSG

@@ -1,16 +1,28 @@
-chore: commit pending ZXDB explorer changes prior to index perf work
+perf(zxdb): server-render index pages with ISR and initial data
 
-Context
-- Housekeeping commit to capture all current ZXDB Explorer work before index-page performance optimizations.
+Why
+- Reduce time-to-first-content on ZXDB index pages by eliminating the initial client-side fetch and enabling incremental static regeneration.
 
-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.
+What
+- Main Explorer (/zxdb):
+  - Server-renders first page of results and lookup lists (genres, languages, machinetypes) and passes them as initial props.
+  - Keeps client interactivity for subsequent searches/filters.
+- Labels index (/zxdb/labels):
+  - Server-renders first page of empty search and passes as initial props to skip the first fetch.
+- Category lists:
+  - Genres (/zxdb/genres), Languages (/zxdb/languages), Machine Types (/zxdb/machinetypes) now server-render their lists and export revalidate=3600.
+  - Refactored list components to accept server-provided items; removed on-mount fetching.
+- Links & prefetch:
+  - Replaced remaining anchors with Next Link to enable prefetch where applicable.
+
+Tech details
+- Added revalidate=3600 to the index pages for ISR.
+- Updated ZxdbExplorer to accept initial results and initial filter lists; skips first client fetch when initial props are present.
+- Updated LabelsSearch to accept initial payload and skip first fetch in default state.
+- Updated GenreList, LanguageList, MachineTypeList to be presentational components receiving items from server pages.
 
 Notes
-- Follow-up commit will focus specifically on speeding up index pages via SSR initial data and ISR.
+- Low-churn list APIs already emit Cache-Control for CDN; list pages now render instantly from server.
+- Further polish (breadcrumbs, facet counts UI) can build on this foundation without reintroducing initial network waits.
 
 Signed-off-by: Junie@lucy.xalior.com

src/app/zxdb/ZxdbExplorer.tsx

@@ -18,14 +18,24 @@ type Paged<T> = {
   total: number;
 };
 
-export default function ZxdbExplorer() {
+export default function ZxdbExplorer({
+  initial,
+  initialGenres,
+  initialLanguages,
+  initialMachines,
+}: {
+  initial?: Paged<Item>;
+  initialGenres?: { id: number; name: string }[];
+  initialLanguages?: { id: string; name: string }[];
+  initialMachines?: { id: number; name: string }[];
+}) {
   const [q, setQ] = useState("");
   const [page, setPage] = useState(1);
   const [loading, setLoading] = useState(false);
-  const [data, setData] = useState<Paged<Item> | null>(null);
-  const [genres, setGenres] = useState<{ id: number; name: string }[]>([]);
-  const [languages, setLanguages] = useState<{ id: string; name: string }[]>([]);
-  const [machines, setMachines] = useState<{ id: number; name: string }[]>([]);
+  const [data, setData] = useState<Paged<Item> | null>(initial ?? null);
+  const [genres, setGenres] = useState<{ id: number; name: string }[]>(initialGenres ?? []);
+  const [languages, setLanguages] = useState<{ id: string; name: string }[]>(initialLanguages ?? []);
+  const [machines, setMachines] = useState<{ id: number; name: string }[]>(initialMachines ?? []);
   const [genreId, setGenreId] = useState<number | "">("");
   const [languageId, setLanguageId] = useState<string | "">("");
   const [machinetypeId, setMachinetypeId] = useState<number | "">("");
@@ -59,18 +69,23 @@ export default function ZxdbExplorer() {
   }
 
   useEffect(() => {
+    // Avoid immediate client fetch on first paint if server provided initial data
+    if (initial && page === 1 && q === "" && genreId === "" && languageId === "" && machinetypeId === "" && sort === "title") {
+      return;
+    }
     fetchData(q, page);
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [page, genreId, languageId, machinetypeId, sort]);
 
-  // Load filter lists once
+  // Load filter lists on mount only if not provided by server
   useEffect(() => {
+    if (initialGenres && initialLanguages && initialMachines) return;
     async function loadLists() {
       try {
         const [g, l, m] = await Promise.all([
-          fetch("/api/zxdb/genres", { cache: "no-store" }).then((r) => r.json()),
-          fetch("/api/zxdb/languages", { cache: "no-store" }).then((r) => r.json()),
-          fetch("/api/zxdb/machinetypes", { cache: "no-store" }).then((r) => r.json()),
+          fetch("/api/zxdb/genres", { cache: "force-cache" }).then((r) => r.json()),
+          fetch("/api/zxdb/languages", { cache: "force-cache" }).then((r) => r.json()),
+          fetch("/api/zxdb/machinetypes", { cache: "force-cache" }).then((r) => r.json()),
         ]);
         setGenres(g.items ?? []);
         setLanguages(l.items ?? []);
@@ -78,7 +93,7 @@ export default function ZxdbExplorer() {
       } catch {}
     }
     loadLists();
-  }, []);
+  }, [initialGenres, initialLanguages, initialMachines]);
 
   function onSubmit(e: React.FormEvent) {
     e.preventDefault();

src/app/zxdb/genres/GenreList.tsx

@@ -1,27 +1,10 @@
 "use client";
 
-import { useEffect, useState } from "react";
 import Link from "next/link";
 
 type Genre = { id: number; name: string };
 
-export default function GenreList() {
-  const [items, setItems] = useState<Genre[]>([]);
-  const [loading, setLoading] = useState(true);
-  useEffect(() => {
-    async function load() {
-      try {
-        const res = await fetch("/api/zxdb/genres", { cache: "no-store" });
-        const json = await res.json();
-        setItems(json.items ?? []);
-      } finally {
-        setLoading(false);
-      }
-    }
-    load();
-  }, []);
-
-  if (loading) return <div>Loading…</div>;
+export default function GenreList({ items }: { items: Genre[] }) {
   return (
     <div>
       <h1>Genres</h1>

src/app/zxdb/genres/page.tsx

@@ -1,7 +1,11 @@
 import GenreList from "./GenreList";
+import { listGenres } from "@/server/repo/zxdb";
 
 export const metadata = { title: "ZXDB Genres" };
 
-export default function Page() {
-  return <GenreList />;
+export const revalidate = 3600;
+
+export default async function Page() {
+  const items = await listGenres();
+  return <GenreList items={items as any} />;
 }

src/app/zxdb/labels/LabelsSearch.tsx

@@ -1,16 +1,17 @@
 "use client";
 
-import { useEffect, useMemo, useState } from "react";
+import { useEffect, useMemo, useRef, useState } from "react";
 import Link from "next/link";
 
 type Label = { id: number; name: string; labeltypeId: string | null };
 type Paged<T> = { items: T[]; page: number; pageSize: number; total: number };
 
-export default function LabelsSearch() {
+export default function LabelsSearch({ initial }: { initial?: Paged<Label> }) {
   const [q, setQ] = useState("");
   const [page, setPage] = useState(1);
-  const [data, setData] = useState<Paged<Label> | null>(null);
+  const [data, setData] = useState<Paged<Label> | null>(initial ?? null);
   const [loading, setLoading] = useState(false);
+  const firstLoadSkipped = useRef(false);
   const pageSize = 20;
   const totalPages = useMemo(() => (data ? Math.max(1, Math.ceil(data.total / data.pageSize)) : 1), [data]);
 
@@ -32,6 +33,11 @@ export default function LabelsSearch() {
   }
 
   useEffect(() => {
+    // If server provided initial data for first page of empty search, skip first fetch
+    if (!firstLoadSkipped.current && initial && !q && page === 1) {
+      firstLoadSkipped.current = true;
+      return;
+    }
     load();
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [page]);

src/app/zxdb/labels/page.tsx

@@ -1,7 +1,12 @@
 import LabelsSearch from "./LabelsSearch";
+import { searchLabels } from "@/server/repo/zxdb";
 
 export const metadata = { title: "ZXDB Labels" };
 
-export default function Page() {
-  return <LabelsSearch />;
+export const revalidate = 3600;
+
+export default async function Page() {
+  // Server-render first page of empty search for instant content
+  const initial = await searchLabels({ page: 1, pageSize: 20 });
+  return <LabelsSearch initial={initial as any} />;
 }

src/app/zxdb/languages/LanguageList.tsx

@@ -1,27 +1,10 @@
 "use client";
 
-import { useEffect, useState } from "react";
 import Link from "next/link";
 
 type Language = { id: string; name: string };
 
-export default function LanguageList() {
-  const [items, setItems] = useState<Language[]>([]);
-  const [loading, setLoading] = useState(true);
-  useEffect(() => {
-    async function load() {
-      try {
-        const res = await fetch("/api/zxdb/languages", { cache: "no-store" });
-        const json = await res.json();
-        setItems(json.items ?? []);
-      } finally {
-        setLoading(false);
-      }
-    }
-    load();
-  }, []);
-
-  if (loading) return <div>Loading…</div>;
+export default function LanguageList({ items }: { items: Language[] }) {
   return (
     <div>
       <h1>Languages</h1>

src/app/zxdb/languages/page.tsx

@@ -1,7 +1,11 @@
 import LanguageList from "./LanguageList";
+import { listLanguages } from "@/server/repo/zxdb";
 
 export const metadata = { title: "ZXDB Languages" };
 
-export default function Page() {
-  return <LanguageList />;
+export const revalidate = 3600;
+
+export default async function Page() {
+  const items = await listLanguages();
+  return <LanguageList items={items as any} />;
 }

src/app/zxdb/machinetypes/MachineTypeList.tsx

@@ -1,33 +1,17 @@
 "use client";
 
-import { useEffect, useState } from "react";
+import Link from "next/link";
 
 type MT = { id: number; name: string };
 
-export default function MachineTypeList() {
-  const [items, setItems] = useState<MT[]>([]);
-  const [loading, setLoading] = useState(true);
-  useEffect(() => {
-    async function load() {
-      try {
-        const res = await fetch("/api/zxdb/machinetypes", { cache: "no-store" });
-        const json = await res.json();
-        setItems(json.items ?? []);
-      } finally {
-        setLoading(false);
-      }
-    }
-    load();
-  }, []);
-
-  if (loading) return <div>Loading…</div>;
+export default function MachineTypeList({ items }: { items: MT[] }) {
   return (
     <div>
       <h1>Machine Types</h1>
       <ul className="list-group">
         {items.map((m) => (
           <li key={m.id} className="list-group-item d-flex justify-content-between align-items-center">
-            <a href={`/zxdb/machinetypes/${m.id}`}>{m.name}</a>
+            <Link href={`/zxdb/machinetypes/${m.id}`}>{m.name}</Link>
             <span className="badge text-bg-light">#{m.id}</span>
           </li>
         ))}

src/app/zxdb/machinetypes/page.tsx

@@ -0,0 +1,11 @@
+import MachineTypeList from "./MachineTypeList";
+import { listMachinetypes } from "@/server/repo/zxdb";
+
+export const metadata = { title: "ZXDB Machine Types" };
+
+export const revalidate = 3600;
+
+export default async function Page() {
+  const items = await listMachinetypes();
+  return <MachineTypeList items={items as any} />;
+}

src/app/zxdb/page.tsx

@@ -1,5 +1,5 @@
 import ZxdbExplorer from "./ZxdbExplorer";
-import { searchEntries } from "@/server/repo/zxdb";
+import { searchEntries, listGenres, listLanguages, listMachinetypes } from "@/server/repo/zxdb";
 
 export const metadata = {
   title: "ZXDB Explorer",
@@ -9,6 +9,18 @@ export const revalidate = 3600;
 
 export default async function Page() {
   // Server-render initial page (no query) to avoid first client fetch
-  const initial = await searchEntries({ page: 1, pageSize: 20, sort: "id_desc" });
-  return <ZxdbExplorer initial={initial as any} />;
+  const [initial, genres, langs, machines] = await Promise.all([
+    searchEntries({ page: 1, pageSize: 20, sort: "id_desc" }),
+    listGenres(),
+    listLanguages(),
+    listMachinetypes(),
+  ]);
+  return (
+    <ZxdbExplorer
+      initial={initial as any}
+      initialGenres={genres as any}
+      initialLanguages={langs as any}
+      initialMachines={machines as any}
+    />
+  );
 }