Alpine nginx includes conf.d/*.conf inside the http{} block, but our
template contained map/log_format directives and a server{} block that
conflicted with the include structure. Switched to a complete standalone
nginx.conf with proper user/events/http nesting.
- src/main.server.ts: process.env['SSR_API_BASE_URL'] instead of
process.env.SSR_API_BASE_URL to satisfy TS4111 index signature rule.
- server.spec.ts: update corresponding test assertions to match new syntax.