P1.5: drop SuccessExitCodes field and exit-code flexibility

Remove the SuccessExitCodes field from domain.Job and every layer that
read or wrote it: runner/exitcodes.go (deleted), runner.go runStateDetail
simplified to 0=OK / non-zero=Failed, logfile.go, format.go, operations.go,
store.go, job_dialog.go, and jobs_view.go. Tests updated accordingly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/format.go

@@ -50,15 +50,6 @@ func DisplayArguments(arguments string) string {
 	return strings.TrimSpace(arguments)
 }
 
-// DisplaySuccessExitCodes formats a job's success exit codes for display:
-// "0" (the default) if empty, else the trimmed codes.
-func DisplaySuccessExitCodes(codes string) string {
-	if strings.TrimSpace(codes) == "" {
-		return "0"
-	}
-	return strings.TrimSpace(codes)
-}
-
 // DisplayRunMode formats a job's execution mode: "Start only" or
 // "Wait for completion".
 func DisplayRunMode(job domain.Job) string {

src/app/format_test.go

@@ -68,15 +68,6 @@ func TestDisplayArguments(t *testing.T) {
 	}
 }
 
-func TestDisplaySuccessExitCodes(t *testing.T) {
-	if got := DisplaySuccessExitCodes("  "); got != "0" {
-		t.Errorf("empty codes = %q, want %q", got, "0")
-	}
-	if got := DisplaySuccessExitCodes(" 0,1 "); got != "0,1" {
-		t.Errorf("codes = %q, want %q", got, "0,1")
-	}
-}
-
 func TestDisplayRunMode(t *testing.T) {
 	if got := DisplayRunMode(domain.Job{StartOnly: true}); got != "Start only" {
 		t.Errorf("start-only = %q, want %q", got, "Start only")

src/app/operations.go

@@ -436,8 +436,6 @@ func runningOutput(job domain.Job, trigger string, started time.Time) string {
 	builder.WriteString(job.Command + "\n\n")
 	builder.WriteString("arguments:\n")
 	builder.WriteString(runner.LogArguments(job.Arguments))
-	builder.WriteString("\n\nsuccess_exit_codes:\n")
-	builder.WriteString(runner.SuccessExitCodesText(job))
 	builder.WriteString("\n\nstart_only:\n")
 	builder.WriteString(fmt.Sprintf("%t", job.StartOnly))
 	return builder.String()
@@ -451,10 +449,6 @@ func normalizeJob(job *domain.Job) {
 	job.Schedule = strings.TrimSpace(job.Schedule)
 	job.Command = strings.TrimSpace(job.Command)
 	job.Arguments = strings.TrimSpace(job.Arguments)
-	job.SuccessExitCodes = strings.TrimSpace(job.SuccessExitCodes)
-	if job.SuccessExitCodes == "" {
-		job.SuccessExitCodes = "0"
-	}
 }
 
 // validateJob enforces the minimum executable definition: name, schedule, and