feat: complete v0.5 operations foundation

app/api/health/route.ts

@@ -0,0 +1,11 @@
+import { NextResponse } from "next/server";
+import { db } from "@/lib/db";
+
+export const dynamic = "force-dynamic";
+export async function GET() {
+  try {
+    db.prepare("SELECT 1").get();
+    const failedJobs = Number((db.prepare("SELECT count(*) AS count FROM sync_jobs WHERE status='failed'").get() as { count: number }).count);
+    return NextResponse.json({ ok: true, version: process.env.APP_VERSION || "development", database: "ok", failedJobs, timestamp: new Date().toISOString() });
+  } catch { return NextResponse.json({ ok: false, database: "error" }, { status: 503 }); }
+}