feat: implement Prisma client and standalone database initialization script

scripts/init-db.mjs

@@ -0,0 +1,53 @@
+#!/usr/bin/env node
+/**
+ * Database initialization script.
+ * Run BEFORE the Next.js server starts (via entrypoint.sh).
+ * Uses better-sqlite3 directly — no Prisma CLI dependency.
+ */
+
+import Database from 'better-sqlite3';
+import { existsSync, mkdirSync } from 'fs';
+import { dirname } from 'path';
+
+const DB_URL = process.env.DATABASE_URL || 'file:/app/prisma/dev.db';
+const DB_PATH = DB_URL.replace(/^file:/, '');
+
+// Ensure the directory exists
+const dir = dirname(DB_PATH);
+if (!existsSync(dir)) {
+  mkdirSync(dir, { recursive: true });
+  console.log(`[init-db] Created directory: ${dir}`);
+}
+
+console.log(`[init-db] Initializing database at: ${DB_PATH}`);
+
+const db = new Database(DB_PATH);
+
+// Config table
+db.exec(`
+  CREATE TABLE IF NOT EXISTS "Config" (
+    "id"    TEXT NOT NULL PRIMARY KEY,
+    "value" TEXT NOT NULL
+  );
+`);
+
+// Button table
+db.exec(`
+  CREATE TABLE IF NOT EXISTS "Button" (
+    "id"    INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "name"  TEXT NOT NULL,
+    "url"   TEXT NOT NULL,
+    "order" INTEGER NOT NULL DEFAULT 0
+  );
+`);
+
+// Migration v2: icon column
+try {
+  db.exec(`ALTER TABLE "Button" ADD COLUMN "icon" TEXT;`);
+  console.log('[init-db] Migration: Button.icon column added.');
+} catch {
+  // Column already exists — safe to ignore
+}
+
+db.close();
+console.log('[init-db] Database ready.');