api: env config, fastify with /healthz and SPA static serving

Task: M0-T3

apps/api/src/index.ts

@@ -1,4 +1,19 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
-import { APP_NAME } from '@selfphoneng/shared';
+import { buildApp } from './app.ts';
+import { ConfigError, loadConfig } from './config.ts';
 
-console.log(`${APP_NAME} api`);
+let config;
+try {
+  config = loadConfig();
+} catch (err) {
+  if (!(err instanceof ConfigError)) throw err;
+  console.error(err.message);
+  process.exit(1);
+}
+
+const app = buildApp(config);
+await app.listen({ host: '127.0.0.1', port: config.API_PORT });
+
+for (const sig of ['SIGTERM', 'SIGINT'] as const) {
+  process.once(sig, () => void app.close().then(() => process.exit(0)));
+}