fix(14-02): parity:upstream writes its sidecar on interrupt or SIGTERM

- the command context had no signal handling, so stopping the proxy
  killed it before Flush and no sidecar was ever written
- a background proxy (SIGINT ignored by the shell) now stops on SIGTERM

cmd/summer/parity.go

@@ -4,8 +4,10 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"os/signal"
 	"path/filepath"
 	"strings"
+	"syscall"
 	"time"
 
 	"git.golem15.com/golem15/summercms/modules/bonfire"
@@ -140,6 +142,12 @@ func runParityUpstream(ctx context.Context, in bonfire.Input, out bonfire.Output
 	out.Info(fmt.Sprintf("upstream proxy listening on %s", listen))
 	out.Info(fmt.Sprintf("parity CA certificate: %s", certPath))
 	out.Info(fmt.Sprintf("point the reference backend at it: HTTPS_PROXY=http://%s, curl.cainfo and openssl.cafile=%s", listen, certPath))
+	// The sidecar is written only after the proxy stops, so an interrupt or
+	// SIGTERM must end serving gracefully instead of killing the process. A
+	// shell starts background jobs with SIGINT ignored; NotifyContext
+	// re-enables it.
+	ctx, stop := signal.NotifyContext(ctx, os.Interrupt, syscall.SIGTERM)
+	defer stop()
 	if err := proxy.ListenAndServe(ctx); err != nil {
 		return err
 	}