PROTOCOL.md + away-channel fallthrough

PROTOCOL.md: generated from internal/voice/wire.go — documents the
voice wire format (TCP, length-prefixed JSON, methods, pushes, errors)
for multi-client implementors. Must stay in sync with wire.go.

dispatcher: when voice sink returns ErrVoiceNoSession, skip voice and
continue to remaining channels instead of aborting. sev4-present
already has ntfy in the routing table (continues naturally). sev1-3
present have only voice — the loop ends with no dispatches, which
matches the spec (care/ops-soft drop on no-voice).

voicesink: maps voice.ErrNoSession to delivery.ErrVoiceNoSession so
the dispatcher can detect it without importing the voice package.

internal/delivery/channel.go

@@ -27,10 +27,20 @@
 package delivery
 
 import (
+	"errors"
+
 	"github.com/kami/maven/internal/loop"
 	"github.com/kami/maven/internal/store"
 )
 
+// ErrVoiceNoSession — sentinel returned by the voice sink when no live
+// client session exists at push time. The dispatcher treats this as a
+// skip-continue: the voice channel is unavailable for this delivery, but
+// remaining channels (ntfy, telegram) should still fire. The voicesink
+// maps voice.ErrNoSession to this sentinel so the dispatcher doesn't need
+// to import the voice package.
+var ErrVoiceNoSession = errors.New("delivery: voice: no live session")
+
 // Channel — one delivery transport. Drop is an explicit no-op (the routing
 // table chose to suppress, which is a decision, not a failure — "a missed
 // water nudge is noise"). a nil Sink for a wired channel is a daemon config

internal/delivery/dispatcher.go

@@ -2,7 +2,9 @@ package delivery
 
 import (
 	"context"
+	"errors"
 	"fmt"
+	"log"
 	"time"
 
 	"github.com/kami/maven/internal/loop"
@@ -104,6 +106,10 @@ func (d *Dispatcher) DispatchNudge(ctx context.Context, pn PhrasedNudge, now tim
 			continue
 		}
 		if err := sink.Send(ctx, s); err != nil {
+			if errors.Is(err, ErrVoiceNoSession) {
+				log.Printf("dispatcher: no live voice session for %s, falling through", c.Rule.Name)
+				continue
+			}
 			return out, fmt.Errorf("send %s: %w", ch, err)
 		}
 		// record AFTER successful send — a failed send must not pollute the
@@ -151,6 +157,10 @@ func (d *Dispatcher) DispatchReminder(ctx context.Context, pr PhrasedReminder, n
 			continue
 		}
 		if err := sink.Send(ctx, s); err != nil {
+			if errors.Is(err, ErrVoiceNoSession) {
+				log.Printf("dispatcher: no live voice session for reminder %d, falling through", rd.Reminder.ID)
+				continue
+			}
 			return out, fmt.Errorf("send %s: %w", ch, err)
 		}
 		out = append(out, Dispatch{Sendable: s})

internal/delivery/voicesink/voicesink.go

@@ -94,8 +94,8 @@ func (s *Sink) Send(ctx context.Context, send delivery.Sendable) error {
 	}
 	if err := s.sess.PushToMostRecent(ctx, push); err != nil {
 		if errors.Is(err, voice.ErrNoSession) {
-			log.Printf("voicesink: no live voice session for %s — rerouting deferred, dropping", send.RuleName)
-			return err
+			log.Printf("voicesink: no live voice session for %s, falling through to away channels", send.RuleName)
+			return delivery.ErrVoiceNoSession
 		}
 		return fmt.Errorf("voicesink: push: %w", err)
 	}