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/simulator_test.go

@@ -428,20 +428,22 @@ func newSimWorld(t *testing.T, sc scenario) *simWorld {
 	rtr := buildRouter(emb, matcher, config.DefaultRouterThreshold, router.NewLLMRouter(scripted))
 
 	w.handler = &reactiveHandler{
-		stt:                simTranscriber{},
-		tts:                simSynthesizer{},
-		router:             rtr,
-		embedder:           emb,
+		stt:    simTranscriber{},
+		tts:    simSynthesizer{},
+		router: rtr,
+		recall: recallWiring{
+			embedder:  emb,
+			memStore:  st.VectorMemory(),
+			minScore:  config.DefaultQueryMinScore,
+			minMargin: config.DefaultQueryMinMargin,
+		},
 		api:                api,
 		matcher:            matcher,
 		tools:              tool.NewExecutor(api, 5*time.Second),
 		phraser:            phraser.NewStub(),
 		replier:            newLLMReplier(scripted, nil),
 		now:                clock.Now,
-		memStore:           st.VectorMemory(),
 		dataStore:          st,
-		queryMinScore:      config.DefaultQueryMinScore,
-		queryMinMargin:     config.DefaultQueryMinMargin,
 		timeParser:         router.StubDateTimeParser{},
 		dialogueSessions:   dialogue.NewSessionStore(time.Hour),
 		clarifyStore:       dialogue.NewClarifyStore(time.Hour),