Stop reporting a blocker the task is no longer blocked on

F67. TaskCorrected cleared the standing question when a task resumed and
left Blocker and BlockReason in place, so task 29 ran through implement,
review and submission still reporting block_reason plan_mismatch. Every
surface that reads the projection rather than the event log showed a stop
that had already been answered.

The blocker has the same lifetime as the question beside it, and is now
cleared with it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CVbaKucEYBjMqVeUgJUsc1

internal/operations/planmismatch_test.go

@@ -225,6 +225,10 @@ func TestHumanAnswerResumesTheSamePlanWithoutResealing(t *testing.T) {
 	if after.State != domain.StateQueued {
 		t.Fatalf("state = %s after the human answered, want queued", after.State)
 	}
+	// F67: the stop is over, so the projection must not keep reporting it.
+	if after.BlockReason != "" || after.Blocker != "" {
+		t.Fatalf("a resumed task still reports its blocker: %q %q", after.BlockReason, after.Blocker)
+	}
 	if after.PlanRef != planRef {
 		t.Fatal("answering the question replaced the plan")
 	}