fix: instant graceful shutdown for SSE/WS connections and container stop

cmd/server/main.go

@@ -5,6 +5,7 @@ import (
 	"embed"
 	"io/fs"
 	"log/slog"
+	"net"
 	"net/http"
 	"os"
 	"os/signal"
@@ -58,9 +59,15 @@ func main() {
 
 	srv := api.NewServer(cfg, store, wsHub, staticFS)
 
+	serverCtx, serverCancel := context.WithCancel(context.Background())
+	defer serverCancel()
+
 	httpServer := &http.Server{
-		Addr:         ":" + cfg.Port,
-		Handler:      srv.Router(),
+		Addr:    ":" + cfg.Port,
+		Handler: srv.Router(),
+		BaseContext: func(l net.Listener) context.Context {
+			return serverCtx
+		},
 		ReadTimeout:  15 * time.Second,
 		WriteTimeout: 30 * time.Second,
 		IdleTimeout:  60 * time.Second,
@@ -79,7 +86,12 @@ func main() {
 	<-stop
 
 	slog.Info("Shutting down MindSift server gracefully...")
-	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	serverCancel()
+	wsHub.Close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
 	defer cancel()
-	_ = httpServer.Shutdown(ctx)
+	if err := httpServer.Shutdown(ctx); err != nil {
+		slog.Warn("HTTP server shutdown finished with error", "error", err)
+	}
 }