Add httpserver package: TLS HTTP server with chi

- Server wrapping chi.Mux + http.Server with TLS 1.3 minimum
- ListenAndServeTLS and graceful Shutdown
- LoggingMiddleware (method, path, status, duration, remote)
- StatusWriter for status code capture in middleware
- WriteJSON and WriteError helpers
- 8 tests

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

go.mod

@@ -3,6 +3,7 @@ module git.wntrmute.dev/kyle/mcdsl
 go 1.25.7
 
 require (
+	github.com/go-chi/chi/v5 v5.2.5
 	github.com/pelletier/go-toml/v2 v2.3.0
 	modernc.org/sqlite v1.47.0
 )