feat(memory): AW-backed Store with over-fetch kind filtering

internal/memory/memory.go

@@ -8,6 +8,8 @@ import (
 	"context"
 	"sync"
 	"time"
+
+	"keel/internal/aw"
 )
 
 // Event is one derived event Keel chooses to remember. Kind is the event type
@@ -68,3 +70,63 @@ func (f *Fake) Events() []Event {
 	defer f.mu.Unlock()
 	return append([]Event(nil), f.events...)
 }
+
+// overfetch bounds how many recent bucket events awStore pulls before filtering
+// by kind, because keel.events interleaves all kinds. Events older than this
+// window are not seen — acceptable for "recent".
+const overfetch = 200
+
+// kindKey is the data field carrying the Event.Kind inside an AW event.
+const kindKey = "_kind"
+
+// AWClient is the subset of *aw.Client that awStore needs. Declaring it here
+// lets tests inject a fake without HTTP; *aw.Client satisfies it structurally.
+type AWClient interface {
+	Insert(ctx context.Context, bucketID string, e aw.Event) error
+	Recent(ctx context.Context, bucketID string, limit int) ([]aw.Event, error)
+}
+
+type awStore struct {
+	c        AWClient
+	bucketID string
+}
+
+// NewAWStore returns a Store that persists events to the given AW bucket.
+func NewAWStore(c AWClient, bucketID string) Store {
+	return &awStore{c: c, bucketID: bucketID}
+}
+
+func (s *awStore) Record(ctx context.Context, e Event) error {
+	data := make(map[string]any, len(e.Data)+1)
+	for k, v := range e.Data {
+		data[k] = v
+	}
+	data[kindKey] = e.Kind
+	return s.c.Insert(ctx, s.bucketID, aw.Event{Timestamp: e.At, Duration: 0, Data: data})
+}
+
+func (s *awStore) Recent(ctx context.Context, kind string, n int) ([]Event, error) {
+	if n <= 0 {
+		return nil, nil
+	}
+	raw, err := s.c.Recent(ctx, s.bucketID, overfetch)
+	if err != nil {
+		return nil, err
+	}
+	var out []Event
+	for _, ev := range raw {
+		if len(out) >= n {
+			break
+		}
+		if k, _ := ev.Data[kindKey].(string); k == kind {
+			data := make(map[string]any, len(ev.Data))
+			for dk, dv := range ev.Data {
+				if dk != kindKey {
+					data[dk] = dv
+				}
+			}
+			out = append(out, Event{Kind: kind, At: ev.Timestamp, Data: data})
+		}
+	}
+	return out, nil
+}