fix: Datenbank-Connection lazy initialisieren für Build-Kompatibilität

lib/db.ts

 import { Pool } from 'pg'
 
-const connectionString = process.env.DATABASE_URL
+let pool: Pool | undefined
 
-if (!connectionString) {
-  throw new Error('DATABASE_URL environment variable is not set')
-}
+// Lazy initialization of the database pool
+function getPool(): Pool {
+  if (!pool) {
+    const connectionString = process.env.DATABASE_URL
+
+    if (!connectionString) {
+      throw new Error('DATABASE_URL environment variable is not set')
+    }
 
-// Create a singleton pool instance
-const pool = new Pool({
-  connectionString,
-  ssl: process.env.NODE_ENV === 'production' ? { rejectUnauthorized: false } : false,
-})
+    pool = new Pool({
+      connectionString,
+      ssl: process.env.NODE_ENV === 'production' ? { rejectUnauthorized: false } : false,
+    })
 
-// Handle pool errors
-pool.on('error', (err) => {
-  console.error('Unexpected error on idle client', err)
-  process.exit(-1)
-})
+    // Handle pool errors
+    pool.on('error', (err) => {
+      console.error('Unexpected error on idle client', err)
+      process.exit(-1)
+    })
+  }
+
+  return pool
+}
 
-export { pool as db }
+export { getPool as db }
 
 // Helper function to query the database
 export async function query(text: string, params?: unknown[]) {
+  const dbPool = getPool()
   const start = Date.now()
-  const res = await pool.query(text, params)
+  const res = await dbPool.query(text, params)
   const duration = Date.now() - start
   if (process.env.NODE_ENV === 'development') {
     console.log('Executed query', { text, duration, rows: res.rowCount })