Build hn-reader: keyboard-driven Hacker News reader

Vite/React + shadcn/ui frontend with Superhuman-style keyboard nav
(j/k/o/v/e/s/u, feed switching, localStorage caching for instant
loads) backed by an Express API that polls the HN Firebase API into
Postgres and serves cached feeds/comments. Instrumented with
OpenTelemetry (traces/metrics/logs via OTLP/HTTP).

server/db.js

@@ -0,0 +1,11 @@
+const { Pool } = require('pg')
+
+const pool = new Pool({
+  host: process.env.POSTGRES_HOST || '127.0.0.1',
+  port: Number(process.env.POSTGRES_PORT || 5433),
+  database: process.env.POSTGRES_DB || 'hnreader',
+  user: process.env.POSTGRES_USER || 'hnreader',
+  password: process.env.POSTGRES_PASSWORD,
+})
+
+module.exports = { pool }