fix: code-review findings on overnight-jul5

- digest queue no longer dropped on failed dispatch (retry next tick)
- collapsed reminders marked fired/rescheduled only after digest delivers
- /tools step-up gate skipped when WebAuthn is not configured (was 403 forever)
- passkey credential store rolls back memory on persist failure
- auth_test fake updated for TickTrace (branch build break)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ASstMtsZWLSRcD1Tq8T68Q

internal/loop/gather.go

@@ -12,7 +12,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"log"
 	"time"
 
 	"github.com/kami/maven/internal/store"
@@ -143,10 +142,7 @@ func (g *Gatherer) GatherState(ctx context.Context, now time.Time) (State, []sto
 	if err != nil {
 		return State{}, nil, err
 	}
-	due, err = collapseReminders(ctx, g.store, due)
-	if err != nil {
-		return State{}, nil, err
-	}
+	due = collapseReminders(due)
 
 	s := State{
 		Now:           now,
@@ -204,12 +200,14 @@ func readFact(ctx context.Context, s *store.Store, key string) (store.Fact, bool
 
 // collapseReminders — when multiple reminders are due at once (e.g. after
 // the daemon was offline), collapse them into a single digest reminder to
-// avoid a burst of individual notifications. All original reminders are
-// marked as fired; the synthetic digest (ID=0) is what gets dispatched.
+// avoid a burst of individual notifications. The synthetic digest (ID=0)
+// carries the originals in Collapsed; the dispatcher completes them (mark
+// fired / reschedule) only after the digest actually delivers, preserving
+// the "failed send leaves the reminder pending" invariant.
 // When 0 or 1 reminders are due, returns them unchanged.
-func collapseReminders(ctx context.Context, s *store.Store, due []store.Reminder) ([]store.Reminder, error) {
+func collapseReminders(due []store.Reminder) []store.Reminder {
 	if len(due) <= 1 {
-		return due, nil
+		return due
 	}
 	// Build a summary payload.
 	var items []string
@@ -235,21 +233,13 @@ func collapseReminders(ctx context.Context, s *store.Store, due []store.Reminder
 		"items": items,
 	})
 
-	// Mark originals as fired so they won't re-fire on next tick.
-	for _, r := range due {
-		if err := s.MarkReminder(ctx, r.ID, "fired"); err != nil {
-			// Log and continue — one failure shouldn't block the digest.
-			// The next tick will re-gather and re-attempt.
-			log.Printf("gather: mark reminder %d fired: %v", r.ID, err)
-		}
-	}
-
 	// Return a single synthetic digest reminder. ID=0 signals "digest" to
-	// the dispatcher (which skips MarkReminder for ID=0).
+	// the dispatcher, which completes the Collapsed originals on success.
 	return []store.Reminder{{
 		ID:        0,
 		FireTs:    earliest,
 		Payload:   string(digestPayload),
 		Status:    "pending",
-	}}, nil
+		Collapsed: due,
+	}}
 }