chore: ZXDB env validation, MySQL setup, API & UI

This sanity commit wires up the initial ZXDB integration and a minimal UI to explore it.

Key changes:
- Add Zod-based env parsing (`src/env.ts`) validating `ZXDB_URL` as a mysql:// URL (t3.gg style).
- Configure Drizzle ORM with mysql2 connection pool (`src/server/db.ts`) driven by `ZXDB_URL`.
- Define minimal ZXDB schema models (`src/server/schema/zxdb.ts`): `entries` and helper `search_by_titles`.
- Implement repository search with pagination using helper table (`src/server/repo/zxdb.ts`).
- Expose Next.js API route `GET /api/zxdb/search` with Zod query validation and Node runtime (`src/app/api/zxdb/search/route.ts`).
- Create new app section “ZXDB Explorer” at `/zxdb` with search UI, results table, and pagination (`src/app/zxdb/*`).
- Add navbar link to ZXDB (`src/components/Navbar.tsx`).
- Update example.env with readonly-role notes and example `ZXDB_URL`.
- Add drizzle-kit config scaffold (`drizzle.config.ts`).
- Update package.json deps: drizzle-orm, mysql2, zod; devDeps: drizzle-kit. Lockfile updated.
- Extend .gitignore to exclude large ZXDB structure dump.

Notes:
- Ensure ZXDB data and helper tables are loaded (see `ZXDB/scripts/ZXDB_help_search.sql`).
- This commit provides structure-only browsing; future work can enrich schema (authors, labels, publishers) and UI filters.

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

src/server/db.ts

@@ -0,0 +1,15 @@
+import mysql from "mysql2/promise";
+import { drizzle } from "drizzle-orm/mysql2";
+import { env } from "@/env";
+
+// Create a singleton connection pool for the ZXDB database
+const pool = mysql.createPool({
+  uri: env.ZXDB_URL,
+  connectionLimit: 10,
+  // Larger queries may be needed for ZXDB
+  maxPreparedStatements: 256,
+});
+
+export const db = drizzle(pool);
+
+export type Db = typeof db;

src/server/repo/zxdb.ts

@@ -0,0 +1,74 @@
+import { and, desc, eq, like, sql } from "drizzle-orm";
+import { db } from "@/server/db";
+import { entries, searchByTitles } from "@/server/schema/zxdb";
+
+export interface SearchParams {
+  q?: string;
+  page?: number; // 1-based
+  pageSize?: number; // default 20
+}
+
+export interface SearchResultItem {
+  id: number;
+  title: string;
+  isXrated: number;
+  machinetypeId: number | null;
+  languageId: string | null;
+}
+
+export interface PagedResult<T> {
+  items: T[];
+  page: number;
+  pageSize: number;
+  total: number;
+}
+
+export async function searchEntries(params: SearchParams): Promise<PagedResult<SearchResultItem>> {
+  const q = (params.q ?? "").trim();
+  const pageSize = Math.max(1, Math.min(params.pageSize ?? 20, 100));
+  const page = Math.max(1, params.page ?? 1);
+  const offset = (page - 1) * pageSize;
+
+  if (q.length === 0) {
+    // Default listing: return first page by id desc (no guaranteed ordering field; using id)
+    const [items, [{ total }]] = await Promise.all([
+      db.select().from(entries).orderBy(desc(entries.id)).limit(pageSize).offset(offset),
+      db.execute(sql`select count(*) as total from ${entries}`) as Promise<any>,
+    ]);
+    return {
+      items: items as any,
+      page,
+      pageSize,
+      total: Number((total as any) ?? 0),
+    };
+  }
+
+  const pattern = `%${q.toLowerCase().replace(/[^a-z0-9]+/g, "")}%`;
+
+  // Count matches via helper table
+  const countRows = await db
+    .select({ total: sql<number>`count(distinct ${searchByTitles.entryId})` })
+    .from(searchByTitles)
+    .where(like(searchByTitles.entryTitle, pattern));
+
+  const total = Number(countRows[0]?.total ?? 0);
+
+  // Items using join to entries, distinct entry ids
+  const items = await db
+    .select({
+      id: entries.id,
+      title: entries.title,
+      isXrated: entries.isXrated,
+      machinetypeId: entries.machinetypeId,
+      languageId: entries.languageId,
+    })
+    .from(searchByTitles)
+    .innerJoin(entries, eq(entries.id, searchByTitles.entryId))
+    .where(like(searchByTitles.entryTitle, pattern))
+    .groupBy(entries.id)
+    .orderBy(entries.title)
+    .limit(pageSize)
+    .offset(offset);
+
+  return { items: items as any, page, pageSize, total };
+}

src/server/schema/zxdb.ts

@@ -0,0 +1,18 @@
+import { mysqlTable, int, varchar, tinyint, char } from "drizzle-orm/mysql-core";
+
+// Minimal subset needed for browsing/searching
+export const entries = mysqlTable("entries", {
+  id: int("id").notNull().primaryKey(),
+  title: varchar("title", { length: 250 }).notNull(),
+  isXrated: tinyint("is_xrated").notNull(),
+  machinetypeId: tinyint("machinetype_id"),
+  languageId: char("language_id", { length: 2 }),
+});
+
+// Helper table created by ZXDB_help_search.sql
+export const searchByTitles = mysqlTable("search_by_titles", {
+  entryTitle: varchar("entry_title", { length: 250 }).notNull(),
+  entryId: int("entry_id").notNull(),
+});
+
+export type Entry = typeof entries.$inferSelect;