feat: switch to standalone output with PocketBase remotePatterns

Drops static export (STATIC_EXPORT env var) in favour of standalone
for ISR. Images remotePatterns reads PB_HOSTNAME/PB_PORT env vars so
Docker internal hostname works without hardcoding.

next.config.ts

@@ -1,13 +1,21 @@
 import type { NextConfig } from 'next';
 
-/* output: 'export' is opt-in via STATIC_EXPORT=true.
- * Set this in CI/deploy — not locally — so the mock API route works
- * during development and local builds. */
-const isExport = process.env.STATIC_EXPORT === 'true';
+/* PocketBase origin — used to allowlist remote images.
+ * PB_HOSTNAME and PB_PORT are server-only env vars; safe to read here. */
+const pbHostname = process.env.PB_HOSTNAME ?? '127.0.0.1';
+const pbPort = parseInt(process.env.PB_PORT ?? '8090', 10);
 
 const nextConfig: NextConfig = {
-  ...(isExport ? { output: 'export' } : {}),
-  images: { unoptimized: true },
+  output: 'standalone',
+  images: {
+    remotePatterns: [
+      {
+        protocol: 'http',
+        hostname: pbHostname,
+        port: String(pbPort),
+      },
+    ],
+  },
   experimental: {
     viewTransition: true,
   },