⚡ Bolt: [performance improvement] concurrent database queries for admin stats

[secrooq]

💡 What: Replaced four sequential db.prepare(...).first() database queries in the admin stats route (src/app/api/admin/[[...slug]]/route.ts) with a single Promise.all array to execute them concurrently. Error handling remains identical via individual chained .catch() blocks to prevent the entire batch from failing if one query errors out.

🎯 Why: In serverless architectures like Cloudflare D1, sequential database queries cause an N+1 latency bottleneck because each query requires a discrete HTTP roundtrip over the network. Executing them concurrently drastically reduces the time spent waiting on network I/O.

📊 Impact: Reduces database query latency for the admin stats endpoint by ~75% (running four queries in the time of one).

🔬 Measurement: Verify by loading the admin dashboard stats endpoint and observing network timings. Build and test suites (pnpm run build, pnpm test, npx playwright test) pass successfully.

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PR created automatically by Jules for task 17886214288374523958 started by @secrooq

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