an embedder error passes instead of ending the turn (V-568)

queryEmbed claimed the turn on a failed EmbedQuery and returned
QueryFailAnswer. It sits above memory, notes, the personal boundary,
search, Kiwix, the named page and general knowledge, so one ONNX error
answered every question below it with "не получилось найти ответ",
including the ones search and Kiwix answer without an embedder at all.

It now logs and passes, the shape turnVector already had. The two recall
sources below pass on an empty vector rather than searching on one, and
queryNotes passes on a store error too: a source that could not look is
not a source that looked and found nothing.

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

cmd/mavend/actions_query.go

@@ -485,7 +485,15 @@ func (h *reactiveHandler) queryWeather(ctx context.Context, t *queryTurn) (strin
 
 // queryEmbed isn't an answer source — it's the shared cost the two recall
 // sources below both need, run once, in the position it always ran in. It
-// only claims the turn when the embedder fails.
+// never claims the turn.
+//
+// It used to claim on an embedder error, and that made a RAG hint a hard gate
+// over everything below it (V-568): one failing EmbedQuery and the memory, the
+// notes, the boundary, the search, the ZIMs, the named page and the model all
+// answered "не смогла ответить", including the questions search and Kiwix
+// would have answered without ever touching the embedder. A failed embed means
+// this source cannot claim, not that the turn is over — same shape as
+// turnVector in topics.go, which had it right.
 func (h *reactiveHandler) queryEmbed(ctx context.Context, t *queryTurn) (string, bool) {
 	// A topic source above already paid for this one; see turnVector.
 	if len(t.vec) > 0 {
@@ -493,8 +501,11 @@ func (h *reactiveHandler) queryEmbed(ctx context.Context, t *queryTurn) (string,
 	}
 	vec, err := router.EmbedQuery(ctx, h.recall.embedder, t.dec.Utterance)
 	if err != nil {
+		// Logged once, here, and the chain walks on. The two recall sources
+		// below read the empty vector and pass; the boundary drops to its
+		// offline floor.
 		log.Printf("voice: embed query: %v", err)
-		return phraser.Q(phraser.QueryFailAnswer, nil), true
+		return "", false
 	}
 	t.vec = vec
 	return "", false
@@ -514,6 +525,12 @@ func (h *reactiveHandler) queryMemory(ctx context.Context, t *queryTurn) (string
 	if h.recall.memStore == nil {
 		return "", false
 	}
+	if len(t.vec) == 0 {
+		// No query vector: the embed above failed or there is no embedder.
+		// Searching on an empty vector is not a search, and its scores are not
+		// a "there is nothing" answer — pass rather than gate the chain.
+		return "", false
+	}
 	hits, herr := h.recall.memStore.Search(ctx, t.vec, 3)
 	if herr != nil {
 		log.Printf("voice: memory search: %v", herr)
@@ -560,10 +577,18 @@ func (h *reactiveHandler) queryMemory(ctx context.Context, t *queryTurn) (string
 // band. See memory.Confident. Failing the gate passes the turn on to general
 // knowledge, which is what "don't read back the runner-up" means here.
 func (h *reactiveHandler) queryNotes(ctx context.Context, t *queryTurn) (string, bool) {
+	if len(t.vec) == 0 {
+		// Same reason as queryMemory above (V-568): with no query vector this
+		// source could not look, and could-not-look passes.
+		return "", false
+	}
 	notes, err := h.api.QueryNotes(ctx, t.vec, 5)
 	if err != nil {
+		// The store failed, so this source could not look either. It used to
+		// claim here, which stopped the search, the ZIMs and the model from
+		// answering a question that never needed a note (V-568).
 		log.Printf("voice: query notes: %v", err)
-		return phraser.Q(phraser.QueryFailAnswer, nil), true
+		return "", false
 	}
 	t.notes = notes
 	noteScores := make([]float64, len(notes))