Ship voice enrolment, and report recognition as blocked (#255)

Maven can now be told who someone is. She cannot yet tell who is speaking,
and this commit is careful to say so rather than pretend otherwise.

What works: profiles are enrolled from several deliberately recorded samples,
listed, and deleted. They live in the existing memory_vectors table under a
"speaker:" id prefix, so there is no migration; what that needed was a wider
interface than memory.Store, hence memory.Catalog with ByPrefix and Delete.
Delete is the load-bearing half — a voiceprint someone asked to be rid of has
to actually go, and a search-only store cannot do that. InMemoryStore.Insert
became an upsert by id to match what the persistent store already did.

What does not work, and why it is not faked: there is no speaker-embedding
model on this box. Sixteen ggufs in /mnt/hdd1/llms, all text; no ECAPA, no
x-vector, no titanet, no wespeaker, no .onnx anywhere under /mnt/hdd1. So
newSpeakerEmbedder returns nil, internal/speaker falls back to
speaker.Disabled, Identify answers ErrDisabled, and the daemon logs which
half is off at startup. The plan's "simple MFCC + GMM" floor is refused in
the package comment: MFCC cosine distance detects channel and loudness as
much as voice, and a biometric that is confidently wrong writes false claims
about named people into his memory. A bad floor is worse than none here.

Refused as well, and the reason is in enroll.go's doc comment: the plan asked
for unknown speakers to be enrolled on first interaction with a TTS "кто
это?". There is no request shape in the protocol that could express that.
Taking a biometric of whoever walks past the microphone does it to guests who
are not party to the exchange, and a synthesised question into a room is not
consent from whoever answers.

Authority: enrolment is AuthStepUp, because it is a deliberate sit-down act
that writes a biometric of a named person and never something done by voice
mid-conversation. Deletion is one rung lower at AuthWrite, deliberately
inverting the usual pattern — getting rid of a biometric must never be the
harder half. Listing is AuthRead and never returns the vectors themselves.

Off unless configured: no speaker block means the three methods answer
ErrUnknownMethod, so a default box has no wire path that takes a voiceprint.

make build and make test pass.

Vikunja #255

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TrVSBKe3RFDF4fGYKWYQnX

cmd/mavend/main.go

@@ -340,6 +340,10 @@ func run(args []string) error {
 		// retention loop. Off unless a capture block enables it, in which case
 		// all four capture methods answer ErrUnknownMethod.
 		wireCapture(srv, keeper, st, voiceW, phr, cfg)
+		// Voice identification (Vikunja #255). Enrolment plumbing only until a
+		// speaker-embedding model exists on disk; off entirely without a speaker
+		// block, so no wire path takes a voiceprint on a default box.
+		wireSpeaker(srv, st, cfg)
 	}
 
 	// WrapKeyFn — wraps the env key with a passkey credential public key and
@@ -485,6 +489,10 @@ func run(args []string) error {
 			wireModelSwap(srv, phr, cfg)
 			keeper := wireVision(ctx, srv, st, embedderOf(voiceW), cfg)
 			wireCapture(srv, keeper, st, voiceW, phr, cfg)
+			// Voice identification (Vikunja #255). Enrolment plumbing only until a
+			// speaker-embedding model exists on disk; off entirely without a speaker
+			// block, so no wire path takes a voiceprint on a default box.
+			wireSpeaker(srv, st, cfg)
 
 			// Start voice server.
 			if voiceW != nil {

cmd/mavend/speaker.go

@@ -0,0 +1,146 @@
+// mavend/speaker.go — core's half of voice identification (Vikunja #255,
+// docs/plans/10-speaker-recognition.md).
+//
+// # What is actually wired here, and what is not
+//
+// The enrolment plumbing is real: profiles are stored, listed and deleted, and
+// the wire methods exist as soon as a speaker block is configured. The
+// recognising half is NOT, and cannot be on this box, because there is no
+// speaker-embedding model on disk — no ECAPA, no x-vector, no titanet, no
+// wespeaker, nothing in /mnt/hdd1/llms but text ggufs. Until one is downloaded,
+// newSpeakerEmbedder returns nil, internal/speaker falls back to
+// speaker.Disabled, and every Identify answers ErrDisabled. The daemon logs
+// which half is off at startup rather than pretending.
+//
+// This is deliberately not papered over with a hand-rolled MFCC floor. A
+// biometric that is confidently wrong writes false claims about named people
+// into his memory, and that is worse than a capability that is honestly absent.
+//
+// # Off unless configured
+//
+// No speaker block, or one without enabled, ⇒ the three methods do not exist and
+// answer ErrUnknownMethod. On an unconfigured box there is no wire path that
+// takes a voiceprint at all.
+//
+// # The refused design step
+//
+// The plan asks for unknown speakers to be enrolled on first interaction. That
+// is refused in internal/speaker/enroll.go and there is no handler for it here:
+// no request shape in the protocol enrols whoever just spoke. Taking a biometric
+// of a guest who walked past the microphone is not something this daemon does.
+package main
+
+import (
+	"context"
+	"errors"
+	"log"
+
+	"github.com/kami/maven/internal/config"
+	"github.com/kami/maven/internal/ipc"
+	"github.com/kami/maven/internal/speaker"
+	"github.com/kami/maven/internal/store"
+)
+
+// speakerWiring holds the recognizer behind the three IPC handlers.
+type speakerWiring struct {
+	rec *speaker.Recognizer
+}
+
+// newSpeakerEmbedder loads the speaker-embedding model named by the config.
+//
+// It always returns nil today. The seam exists so that wiring a real model is a
+// change to this one function and nothing else: give it a loader, and Identify
+// starts working with no change to the store, the protocol, the auth table or
+// the handlers. See the plan document for what to download.
+func newSpeakerEmbedder(cfg *config.SpeakerConfig) speaker.Embedder {
+	if cfg == nil || cfg.ModelPath == "" {
+		return nil
+	}
+	log.Printf("speaker: model_path %q is configured but no embedding backend is built yet; "+
+		"enrolment and deletion work, recognition does not (Vikunja #255)", cfg.ModelPath)
+	return nil
+}
+
+// newSpeakerWiring builds the recognizer, or nil when the capability is off.
+func newSpeakerWiring(st *store.Store, cfg *config.Config) *speakerWiring {
+	if cfg == nil || cfg.Speaker == nil || !cfg.Speaker.Enabled {
+		return nil
+	}
+	if st == nil {
+		log.Print("speaker: enabled but there is no store to keep profiles in; staying off")
+		return nil
+	}
+	rec, err := speaker.New(newSpeakerEmbedder(cfg.Speaker), st.VectorMemory(), speaker.Config{
+		Threshold:  cfg.Speaker.Threshold,
+		MinSeconds: cfg.Speaker.MinSeconds,
+	})
+	if err != nil {
+		log.Printf("speaker: %v; staying off", err)
+		return nil
+	}
+	if rec.Enabled() {
+		log.Printf("speaker: recognition on, threshold %.2f", rec.Threshold())
+	} else {
+		log.Print("speaker: enrolment on, recognition BLOCKED — no speaker-embedding model " +
+			"on this box (see docs/plans/10-speaker-recognition.md)")
+	}
+	return &speakerWiring{rec: rec}
+}
+
+func (w *speakerWiring) enroll(ctx context.Context, req ipc.EnrollSpeakerReq) (ipc.EnrollSpeakerResp, error) {
+	p, err := w.rec.Enroll(ctx, req.ID, req.Name, req.Samples)
+	if err != nil {
+		return ipc.EnrollSpeakerResp{}, speakerErr(err)
+	}
+	return ipc.EnrollSpeakerResp{Speaker: toWireSpeaker(p)}, nil
+}
+
+func (w *speakerWiring) list(ctx context.Context) (ipc.ListSpeakersResp, error) {
+	ps, err := w.rec.List(ctx)
+	if err != nil {
+		return ipc.ListSpeakersResp{}, speakerErr(err)
+	}
+	out := make([]ipc.Speaker, 0, len(ps))
+	for _, p := range ps {
+		out = append(out, toWireSpeaker(p))
+	}
+	return ipc.ListSpeakersResp{Speakers: out, Enabled: w.rec.Enabled()}, nil
+}
+
+func (w *speakerWiring) forget(ctx context.Context, req ipc.ForgetSpeakerReq) error {
+	return speakerErr(w.rec.Forget(ctx, req.ID))
+}
+
+// toWireSpeaker drops the voiceprint. A listing says who is enrolled; it does
+// not hand the biometric back out over the socket.
+func toWireSpeaker(p speaker.Profile) ipc.Speaker {
+	return ipc.Speaker{ID: p.ID, Name: p.Name, Enrolled: p.Enrolled, Samples: p.Samples}
+}
+
+// speakerErr maps the package sentinels onto the wire vocabulary so a surface
+// can tell "you asked wrong" from "core broke".
+func speakerErr(err error) error {
+	switch {
+	case err == nil:
+		return nil
+	case errors.Is(err, speaker.ErrNotFound):
+		return ipc.ErrNoFact
+	case errors.Is(err, speaker.ErrBadID),
+		errors.Is(err, speaker.ErrBadFormat),
+		errors.Is(err, speaker.ErrTooShort):
+		return errors.Join(ipc.ErrBadParams, err)
+	default:
+		return err
+	}
+}
+
+// wireSpeaker attaches the three handlers when the capability is configured.
+func wireSpeaker(srv *ipc.Server, st *store.Store, cfg *config.Config) {
+	w := newSpeakerWiring(st, cfg)
+	if w == nil {
+		return
+	}
+	srv.EnrollSpeakerFn = w.enroll
+	srv.ListSpeakersFn = w.list
+	srv.ForgetSpeakerFn = w.forget
+}