Add meeting capture with explicit start and stop (#253)

Maven can record a meeting when she is told to, transcribe it through the
STT she already has, and write a summary note. The audio lives in the blob
store #252 introduced, under the same retention loop.

Nothing here listens. Recorder.Append is the only way audio enters and it
refuses every frame unless someone explicitly started a session, so audio
arriving at an idle core is dropped rather than buffered. The plan document
asked for a keyword trigger ("maven record" heard in the room) and that is
refused: noticing a keyword means listening to the room, which is the one
behaviour this capability must not have.

Off unless configured twice over. No media block means nowhere to keep
audio, no capture block means no recorder, and in either case the four IPC
methods answer ErrUnknownMethod. On an unconfigured box there is no wire
path that begins a recording at all.

A forgotten session ends itself at max_minutes, checked on every append,
and the audio collected before the cap is kept. Stop with discard set is
what "забудь, не записывай" maps to and it leaves nothing behind. The
verbatim transcript is not saved unless save_transcript says so; the
summary is.

Long audio against n_ctx 4096 is handled by map-reduce over 3000-rune
windows rather than by truncation, because a truncated meeting summary
reads as complete and is not. Transcription is windowed at five minutes so
the whisper worker stays responsive to the voice path.

No second STT: internal/capture takes the stt.Transcriber the voice path
already holds. Capture with voice off is refused rather than degraded,
since hours of unreadable audio of other people is worse than no recording.

The three write methods are AuthWrite, not AuthStepUp: step-up needs a
passkey gesture the voice path cannot make, which would leave "запиши
встречу" impossible by voice. capture_status is AuthRead.

make build and make test both pass.

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

internal/config/config.go

@@ -205,6 +205,13 @@ type Config struct {
 	// in this repo holds a recording only in memory. See MediaConfig.
 	Media *MediaConfig `json:"media,omitempty"`
 
+	// Capture — meeting recording and summarisation (Vikunja #253). nil /
+	// absent ⇒ the recorder does not exist: the start/stop methods are not
+	// served at all, so nothing on this box can begin a recording. This is the
+	// most invasive capability Maven has and it is the one most firmly off by
+	// default. See CaptureConfig.
+	Capture *CaptureConfig `json:"capture,omitempty"`
+
 	// MCP — Model Context Protocol servers Maven connects OUT to (Vikunja
 	// #251). nil / absent / no enabled server ⇒ no connection is made and no
 	// tool is discovered, like every other capability that reaches outside the
@@ -558,6 +565,60 @@ func (v *VisionConfig) LooksAtImages() bool {
 	return v != nil && v.Enabled && strings.TrimSpace(v.Endpoint) != ""
 }
 
+// CaptureConfig — the meeting recorder (internal/capture,
+// docs/plans/08-hearing.md).
+//
+// Absent, or enabled=false, ⇒ the recorder is not wired and the capture methods
+// return "unknown method", so no client can start a recording however it asks.
+// A media block is required too: audio is never held only in memory.
+//
+// There is deliberately no "auto", no keyword trigger and no duration default
+// long enough to be forgotten about. Recording other people is an explicit act
+// with a start, a stop, and a cap.
+type CaptureConfig struct {
+	// Enabled — may she record a meeting when asked. Default false.
+	Enabled bool `json:"enabled,omitempty"`
+
+	// MaxMinutes — hard cap on one session; it stops itself there. 0 ⇒
+	// capture.DefaultMaxDuration (120 minutes).
+	MaxMinutes int `json:"max_minutes,omitempty"`
+
+	// STTWindow — audio handed to whisper per call. 0 ⇒
+	// capture.DefaultSTTWindow (5m). Larger windows transcribe slightly better
+	// and block the STT worker for longer.
+	STTWindow Duration `json:"stt_window,omitempty"`
+
+	// ChunkRunes — transcript runes per summarisation prompt. 0 ⇒
+	// capture.DefaultChunkRunes (3000), sized for the resident model's n_ctx of
+	// 4096. Raise this only if the resident model's context grows.
+	ChunkRunes int `json:"chunk_runes,omitempty"`
+
+	// MaxChunks — how many windows one meeting may be summarised in before the
+	// transcript is truncated and the summary says so. 0 ⇒
+	// capture.DefaultMaxChunks (40).
+	MaxChunks int `json:"max_chunks,omitempty"`
+
+	// SaveTranscript — write the full transcript as a note alongside the
+	// summary. Default false: a verbatim record of what other people said in a
+	// room is a heavier thing to keep than a four-line summary, so it takes a
+	// deliberate yes. The audio blob is pruned by media.retention either way.
+	SaveTranscript bool `json:"save_transcript,omitempty"`
+}
+
+// Records reports whether the recorder should be wired. Safe on a nil receiver.
+func (c *CaptureConfig) Records() bool {
+	return c != nil && c.Enabled
+}
+
+// MaxDuration is the configured session cap as a duration, or 0 for the
+// package default. Safe on a nil receiver.
+func (c *CaptureConfig) MaxDuration() time.Duration {
+	if c == nil || c.MaxMinutes <= 0 {
+		return 0
+	}
+	return time.Duration(c.MaxMinutes) * time.Minute
+}
+
 // WeatherConfig configures the weather provider for voice queries.
 type WeatherConfig struct {
 	Provider        string `json:"provider,omitempty"`         // "open-meteo" or "" → stub

internal/config/senses_test.go

@@ -16,6 +16,70 @@ func TestSensesOffByDefault(t *testing.T) {
 	if cfg.Vision.LooksAtImages() {
 		t.Error("vision is on with no vision block")
 	}
+	if cfg.Capture.Records() {
+		t.Error("the recorder is on with no capture block")
+	}
+	if cfg.Capture.MaxDuration() != 0 {
+		t.Error("a nil capture block invented a duration")
+	}
+}
+
+// The recorder is the capability that most needs its default to be off, so it
+// gets its own test rather than a line in the one above.
+func TestCaptureIsOffUntilExplicitlyEnabled(t *testing.T) {
+	cases := []struct {
+		name string
+		c    *CaptureConfig
+		want bool
+	}{
+		{"absent", nil, false},
+		{"present but not enabled", &CaptureConfig{MaxMinutes: 60}, false},
+		{"enabled", &CaptureConfig{Enabled: true}, true},
+	}
+	for _, c := range cases {
+		if got := c.c.Records(); got != c.want {
+			t.Errorf("%s: Records() = %v, want %v", c.name, got, c.want)
+		}
+	}
+}
+
+func TestCaptureBlockParsesFromJSON(t *testing.T) {
+	raw := `{"capture":{"enabled":true,"max_minutes":45,"stt_window":"2m",
+	  "chunk_runes":2000,"max_chunks":10,"save_transcript":true}}`
+	var cfg Config
+	if err := json.Unmarshal([]byte(raw), &cfg); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if !cfg.Capture.Records() {
+		t.Fatal("capture did not parse as enabled")
+	}
+	if cfg.Capture.MaxDuration() != 45*time.Minute {
+		t.Errorf("max duration = %v", cfg.Capture.MaxDuration())
+	}
+	if time.Duration(cfg.Capture.STTWindow) != 2*time.Minute {
+		t.Errorf("stt window = %v", time.Duration(cfg.Capture.STTWindow))
+	}
+	if cfg.Capture.ChunkRunes != 2000 || cfg.Capture.MaxChunks != 10 {
+		t.Errorf("summariser limits = %+v", cfg.Capture)
+	}
+	if !cfg.Capture.SaveTranscript {
+		t.Error("save_transcript did not parse")
+	}
+}
+
+// Keeping the verbatim record of what other people said is the heavier act, so
+// it is separately opt-in from recording at all.
+func TestTranscriptIsNotSavedByDefault(t *testing.T) {
+	var cfg Config
+	if err := json.Unmarshal([]byte(`{"capture":{"enabled":true}}`), &cfg); err != nil {
+		t.Fatal(err)
+	}
+	if cfg.Capture.SaveTranscript {
+		t.Error("transcripts are saved without anyone asking")
+	}
+	if cfg.Capture.MaxDuration() != 0 {
+		t.Error("max_minutes defaulted in config instead of in the package")
+	}
 }
 
 // enabled with nothing to talk to is a misconfiguration, not a capability.