Keep test daemons out of production's traces and database (#87)

The browser suite's daemon took its environment from the shell running
it, so a shell with OTEL_EXPORTER_OTLP_ENDPOINT set would have sent its
fixture scans to production's Tempo, and one with IPX_DATABASE_URL set
would have run the suite against production's database. Both are now
blanked for it. Production's traces carry
deployment.environment.name=production, which the dashboard filters on,
so a daemon run by hand stays out as well.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

playwright.config.js

@@ -37,6 +37,10 @@ module.exports = defineConfig({
         IPX_CONFIG: `${setup.root}/config/config.toml`,
         IPX_DATA_DIR: `${setup.root}/data`,
         IPX_LOG: 'ipx=info',
+        // Blank, whatever the shell running the suite has: the test daemon sends no traces to
+        // production's Tempo and never opens production's database.
+        OTEL_EXPORTER_OTLP_ENDPOINT: '',
+        IPX_DATABASE_URL: '',
       },
     },
   ],