feat(progress): keyed Fail for a soft failure, Note for the operator, FailRunning for the job's own (ADR-035)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/progress/tracker.go

@@ -21,11 +21,15 @@ type Planned struct {
 
 // Reporter is what a long-running component reports to. Begin starts a phase (total
 // is the number of countable units, 0 when there is no honest count), Advance says how
-// many are done, Done closes the phase.
+// many are done, Done closes the phase. Fail closes a phase that did not work while
+// the job goes on (an engine that was down, the other one's text used instead) and
+// says why in the log. Note is a log line for the operator that costs no write.
 type Reporter interface {
 	Begin(key string, total int)
 	Advance(key string, done int)
 	Done(key string)
+	Fail(key string, err error)
+	Note(msg string, kv ...any)
 }
 
 // Sink is where a job's progress is persisted. Both calls are best effort: progress
@@ -133,9 +137,26 @@ func (t *Tracker) Done(key string) {
 	t.save()
 }
 
-// Fail marks the phase that was running as failed. What never started stays pending,
-// which is what shows the user where the job stopped.
-func (t *Tracker) Fail() {
+// Fail implements Reporter: one phase failed and the job carries on.
+func (t *Tracker) Fail(key string, err error) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	s := t.find(key)
+	if s == nil {
+		return
+	}
+	t.close(s, domain.StepFailed)
+	t.log.Warn("step failed", "step", key, "elapsed", s.FinishedAt.Sub(s.StartedAt), "err", err)
+	t.save()
+}
+
+// Note implements Reporter.
+func (t *Tracker) Note(msg string, kv ...any) { t.log.Info(msg, kv...) }
+
+// FailRunning marks the phase that was running as failed, because the whole job
+// failed. What never started stays pending, which is what shows the user where the
+// job stopped.
+func (t *Tracker) FailRunning() {
 	t.mu.Lock()
 	defer t.mu.Unlock()
 	for i := range t.steps {
@@ -244,3 +265,5 @@ type noop struct{}
 func (noop) Begin(string, int)   {}
 func (noop) Advance(string, int) {}
 func (noop) Done(string)         {}
+func (noop) Fail(string, error)  {}
+func (noop) Note(string, ...any) {}