Fix serving non-existent pages by disabling SPA mode

Dockerfile

@@ -22,6 +22,7 @@ RUN go mod download
 
 # Copy sources
 COPY *.go ./
+COPY default ./default
 
 # Version/Commit (there there is no .git in Docker build context)
 # NOTE: This is fairly low down in the Dockerfile instructions so

main.go

@@ -797,7 +797,6 @@ func serve(ctx context.Context, bind, root string) error {
 		static.WithRoot(root),
 		static.WithCGI(true),
 		static.WithDir(true),
-		static.WithSPA(true),
 	)
 	if err != nil {
 		return err