mesh-knowledge: clear a never-reviewed notice once the record moves on, key it by version and run of tries, say times locally (review of #219)

A notice left open kept telling the operator a record was proposed and not in force after it was proposed again
or accepted, and a later version's notice merged into it.

modules/mesh-knowledge/cmd/mesh-knowledge/store.go

@@ -66,6 +66,9 @@ type Store interface {
 	// Told records that the operator was told of something, once, by its key: a topic's clauses drafted, or a
 	// version that ran out of review tries (novox/hq issue 497); false when it was already.
 	Told(ctx context.Context, topic string) (bool, error)
+	// ToldOf is every key told of that starts with prefix; Untold takes one away once what it told of is over.
+	ToldOf(ctx context.Context, prefix string) ([]string, error)
+	Untold(ctx context.Context, key string) error
 }
 
 // memStore is the Store in memory.
@@ -272,6 +275,26 @@ func (s *memStore) Findings(context.Context) ([]Finding, error) {
 	return append([]Finding(nil), s.findings...), nil
 }
 
+func (s *memStore) ToldOf(_ context.Context, prefix string) ([]string, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	var out []string
+	for k := range s.told {
+		if strings.HasPrefix(k, prefix) {
+			out = append(out, k)
+		}
+	}
+	sort.Strings(out)
+	return out, nil
+}
+
+func (s *memStore) Untold(_ context.Context, key string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	delete(s.told, key)
+	return nil
+}
+
 func (s *memStore) Told(_ context.Context, topic string) (bool, error) {
 	s.mu.Lock()
 	defer s.mu.Unlock()