T1.3: Create src/runner; move runner logic

Move runner.go, runner_windows.go, runner_other.go, runner_test.go from
src/core to src/runner (package runner). Split helpers into focused files:
invocation*.go, exitcodes.go, logfile.go, cleanup.go. Export LogArguments
and SuccessExitCodesText for use by scheduler's runningOutput helper.
Update src/core/scheduler.go and src/gui/app.go to import src/runner.

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

src/runner/runner.go

@@ -0,0 +1,144 @@
+package runner
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os/exec"
+	"strings"
+	"time"
+
+	"gitea.mixdep.ru/mix/gosentry/src/domain"
+	"gitea.mixdep.ru/mix/gosentry/src/platform/winproc"
+)
+
+const commandTimeout = 30 * time.Second
+const commandWaitDelay = 2 * time.Second
+
+func RunJob(ctx context.Context, job *domain.Job, trigger string, logsDir string) domain.RunRecord {
+	started := time.Now()
+	// Commands can hang forever if a script waits for input or a child process
+	// stalls. A fixed timeout is a conservative first guardrail for a desktop
+	// scheduler; later it can become a per-job setting without changing the
+	// runner contract.
+	runCtx, cancel := context.WithTimeout(ctx, commandTimeout)
+	defer cancel()
+
+	var output string
+	var state string
+	var detail string
+	if job.StartOnly {
+		invocation := jobInvocation(context.Background(), *job)
+		state, detail, output = startJobOnly(invocation, *job, started)
+	} else {
+		var stdoutBuf strings.Builder
+		var stderrBuf strings.Builder
+		invocation := jobInvocation(runCtx, *job)
+		command := invocation.command
+		command.WaitDelay = commandWaitDelay
+		if invocation.hideWindow {
+			winproc.ConfigureHiddenWindow(command)
+		}
+		command.Stdout = &stdoutBuf
+		command.Stderr = &stderrBuf
+
+		err := command.Run()
+		duration := time.Since(started).Round(time.Millisecond)
+		output = formatOutput(stdoutBuf.String(), stderrBuf.String())
+		state, detail = runStateDetail(err, runCtx.Err(), duration, *job)
+	}
+
+	now := time.Now()
+	job.LastRun = now.Format("2006-01-02 15:04:05")
+	job.LastState = state
+	job.Output = output
+	logFile := writeRunLog(logsDir, *job, trigger, state, detail, output, now)
+
+	record := domain.RunRecord{
+		Time:    job.LastRun,
+		JobID:   job.ID,
+		JobName: job.Name,
+		Trigger: trigger,
+		State:   state,
+		Detail:  detail,
+		LogFile: logFile,
+		Output:  output,
+	}
+	// Keep a small in-memory history for the currently running GUI. Full command
+	// output is persisted to files, so retaining every past record in RAM would
+	// only duplicate data and make long sessions grow without bound.
+	job.Logs = append([]domain.RunRecord{record}, job.Logs...)
+	if len(job.Logs) > 50 {
+		job.Logs = job.Logs[:50]
+	}
+	return record
+}
+
+func startJobOnly(invocation commandInvocation, job domain.Job, started time.Time) (string, string, string) {
+	command := invocation.command
+	if invocation.hideWindow {
+		winproc.ConfigureHiddenWindow(command)
+	}
+	err := command.Start()
+	duration := time.Since(started).Round(time.Millisecond)
+	if err != nil {
+		return "Failed", fmt.Sprintf("%T: %v", err, err), startOnlyOutput(job, 0)
+	}
+	pid := command.Process.Pid
+	if releaseErr := command.Process.Release(); releaseErr != nil {
+		return "Failed", fmt.Sprintf("process started with pid %d, but release failed: %T: %v", pid, releaseErr, releaseErr), startOnlyOutput(job, pid)
+	}
+	return "OK", fmt.Sprintf("Started in %s (pid %d); not waiting for process exit", duration, pid), startOnlyOutput(job, pid)
+}
+
+func startOnlyOutput(job domain.Job, pid int) string {
+	var builder strings.Builder
+	builder.WriteString("status:\n")
+	if pid > 0 {
+		builder.WriteString(fmt.Sprintf("Started process pid %d. GoSentry is not waiting for it to exit.\n\n", pid))
+	} else {
+		builder.WriteString("Process did not start.\n\n")
+	}
+	builder.WriteString("command:\n")
+	builder.WriteString(job.Command + "\n\n")
+	builder.WriteString("arguments:\n")
+	builder.WriteString(logArguments(job.Arguments))
+	builder.WriteString("\n\nstart_only:\ntrue")
+	return builder.String()
+}
+
+func runStateDetail(err error, runErr error, duration time.Duration, job domain.Job) (string, string) {
+	if err == nil {
+		return "OK", fmt.Sprintf("Completed in %s (exit code 0)", duration)
+	}
+	if errors.Is(runErr, context.DeadlineExceeded) {
+		return "Failed", fmt.Sprintf("Timed out after %s", commandTimeout)
+	}
+	if errors.Is(err, exec.ErrWaitDelay) {
+		return "OK", fmt.Sprintf("Completed; output capture stopped after %s because a child process kept the stream open", commandWaitDelay)
+	}
+
+	var exitError *exec.ExitError
+	if errors.As(err, &exitError) {
+		exitCode := exitError.ExitCode()
+		if acceptedExitCode(exitCode, job.SuccessExitCodes) {
+			return "OK", fmt.Sprintf("Completed in %s with accepted exit code %d", duration, exitCode)
+		}
+		return "Failed", fmt.Sprintf("Exit code %d is not in success_exit_codes (%s)", exitCode, successExitCodesText(job))
+	}
+	return "Failed", fmt.Sprintf("%T: %v", err, err)
+}
+
+func formatOutput(stdout string, stderr string) string {
+	stdout = strings.TrimSpace(stdout)
+	stderr = strings.TrimSpace(stderr)
+	if stdout == "" {
+		// Showing an explicit placeholder is clearer than an empty panel in the
+		// GUI: the user can tell that the command ran but produced no stream data.
+		stdout = "<empty>"
+	}
+	if stderr == "" {
+		stderr = "<empty>"
+	}
+	return "stdout:\n" + stdout + "\n\nstderr:\n" + stderr
+}