add observer runtime model

Instrument command, payload, update, scene, runner, polling, and policy flows
Add observer regression coverage and mark observability backlog item done

runners_test.go

@@ -2,6 +2,7 @@ package laniakea
 
 import (
 	"context"
+	"errors"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -9,6 +10,10 @@ import (
 	"git.scuroneko.dev/scuroneko/slog"
 )
 
+type runnerObserver struct {
+	recordingObserver
+}
+
 func TestExecRunnersRunsOnetimeSyncRunner(t *testing.T) {
 	var calls atomic.Int32
 	bot := &Bot[NoData]{
@@ -60,3 +65,33 @@ func TestExecRunnersStopsBackgroundRunnerOnCancel(t *testing.T) {
 		t.Fatal("expected background runner to be called at least once")
 	}
 }
+
+func TestExecRunnersEmitObserverEvents(t *testing.T) {
+	observer := &runnerObserver{}
+	wantErr := errors.New("runner failed")
+
+	bot := &Bot[NoData]{
+		logger:   slog.CreateLogger(),
+		observer: observer,
+		runners: []Runner[NoData]{
+			NewRunner("sync-once", func(*Bot[NoData]) error {
+				return wantErr
+			}).Onetime(true).Async(false),
+		},
+	}
+
+	bot.ExecRunners(context.Background())
+
+	if len(observer.runners) != 1 {
+		t.Fatalf("expected one runner-finished event, got %d", len(observer.runners))
+	}
+	if got := observer.runners[0]; got.Name != "sync-once" || !errors.Is(got.Err, wantErr) {
+		t.Fatalf("unexpected runner-finished event: %#v", got)
+	}
+	if len(observer.errors) != 1 {
+		t.Fatalf("expected one error event, got %d", len(observer.errors))
+	}
+	if got := observer.errors[0]; got.HandlerKind != HandlerRunnerKind || got.HandlerName != "sync-once" || !errors.Is(got.Err, wantErr) {
+		t.Fatalf("unexpected runner error event: %#v", got)
+	}
+}