mavend: group the recall fields into one wiring struct (V-433)

The review comment asked for basic DI. The answer is the idiom voice.go
already had for capabilities — a cohesive *Wiring struct — applied to a
group that is not a capability toggle, plus the decision written down so
it is a rule and not a habit.

recallWiring holds the embedder, the vector store, the personal boundary
and the two numbers that gate an answer. They sat in three places on
reactiveHandler, with the gate numbers a hundred lines from the store
they gate. Its zero value means no recall, so it is a value, not a
pointer like the optional-capability groups.

dataStore stays out of it. patterns.go, ecosystem_acts.go and confirm.go
use it, so it is not part of this cluster.

docs/handler-wiring.md records the choice, rejects a container or a
wire-style generator outright, defers narrow per-handler interfaces to
the package split that would justify them, and states the constraint the
task named: a wiring change does not ride a feature PR.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

cmd/mavend/actions_fact.go

@@ -73,11 +73,11 @@ func (h *reactiveHandler) actionFact(ctx context.Context, dec router.Decision) s
 	// hears; storing the utterance meant recall answered with his own sentence
 	// rather than the value. The utterance stays alongside as provenance —
 	// readable on /trace, never the answer and never embedded.
-	if h.memStore != nil {
+	if h.recall.memStore != nil {
 		text := store.FactRecallText(dec.Slots.Key, dec.Slots.Value)
-		if vec, err := router.EmbedPassage(ctx, h.embedder, text); err != nil {
+		if vec, err := router.EmbedPassage(ctx, h.recall.embedder, text); err != nil {
 			log.Printf("voice: embed fact for memory: %v", err)
-		} else if err := h.memStore.Insert(ctx, "fact:"+dec.Slots.Key+":"+strconv.FormatInt(now.Unix(), 10), vec, map[string]string{
+		} else if err := h.recall.memStore.Insert(ctx, "fact:"+dec.Slots.Key+":"+strconv.FormatInt(now.Unix(), 10), vec, map[string]string{
 			"source":    "voice",
 			"type":      "fact",
 			"text":      text,