feat(11-02): add schedule:run as a scheduler process and a cron --once mode

- schedule:run runs a worker on the scheduled queue with every plugin's periodic jobs
- schedule:run --once runs entries due in the current app.timezone minute without River,
  warns and skips unregistered commands, and returns the first command error
- summer schedule:run delegate forwards --once
- tests for --once minute matching, forged-entry skipping (T-11-09) and ByPeriod dedupe

cmd/summer/runtime.go

@@ -6,10 +6,11 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strconv"
 	"strings"
 
-	"git.golem15.com/golem15/summercms/modules/bonfire"
 	"git.golem15.com/golem15/summercms/internal/build"
+	"git.golem15.com/golem15/summercms/modules/bonfire"
 )
 
 func delegateCommand(name, description string) bonfire.Command {
@@ -63,6 +64,28 @@ func delegateQueueWorkCommand() bonfire.Command {
 	}
 }
 
+func delegateScheduleRunCommand() bonfire.Command {
+	return bonfire.Command{
+		Name:        "schedule:run",
+		Description: "Run the scheduler in the app binary (or once for system cron)",
+		Flags: []bonfire.Flag{{
+			Name:        "once",
+			Description: "Run the entries due this minute and exit (for system cron)",
+			Bare:        true,
+		}},
+		Run: func(ctx context.Context, in bonfire.Input, out bonfire.Output) error {
+			argv := []string{"schedule:run"}
+			if v, ok := in.Flag("once"); ok {
+				if once, _ := strconv.ParseBool(v); once {
+					argv = append(argv, "--once")
+				}
+			}
+			argv = append(argv, in.Args()...)
+			return runAppBinary(ctx, argv, out)
+		},
+	}
+}
+
 func runAppBinary(ctx context.Context, argv []string, out bonfire.Output) error {
 	if len(argv) == 0 {
 		return fmt.Errorf("summer: missing app command")