feat: notifications say what changed and alert once: a grouped notice names the tracks, grows without re-alerting, and a phone pile lists its titles (M542 #6146-#6151)

- An update to a grouped notice keeps its arrival time and email state, so the
  phone and the email no longer go off again each time it grows.
- Notices carry the names of what changed (newest ten), shown as three and
  "and N more": tracks still missing after the scan's move/replacement fold,
  duplicate groups new to a sweep, songs merged automatically, and the track
  and listener a playback error was for.
- Duplicates found counts only the groups new to that sweep; playback errors
  count reports, not the unresolved total.
- A scan failure says what stopped and links to Admin > Library.
- Android: a pile of more than three alerts lists the newest five titles.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/library/duplicate_resolve.go

@@ -15,7 +15,6 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/notifications"
 	syncpkg "git.fabledsword.com/bvandeusen/minstrel/internal/sync"
-	"git.fabledsword.com/bvandeusen/minstrel/internal/words"
 )
 
 // Duplicate resolver (M498 #5435, #5437; M502 #5517).
@@ -149,6 +148,7 @@ func ResolveDuplicates(
 
 	// Merges before links, so a rip merged away is not linked first.
 	merged := map[pgtype.UUID]bool{}
+	var mergedNames []string
 	for _, g := range groups {
 		if res.Merged >= resolveMergeCap {
 			break
@@ -167,6 +167,9 @@ func ResolveDuplicates(
 		}
 		merged[g.id] = true
 		res.Merged++
+		if len(mergedNames) < notifyItems {
+			mergedNames = append(mergedNames, TrackLabel(g.members[0].ArtistName, g.members[0].Title))
+		}
 	}
 
 	linked, err := linkCrossRelease(ctx, pool, logger, groups, merged)
@@ -177,8 +180,7 @@ func ResolveDuplicates(
 
 	if res.Merged > 0 {
 		notifyAdmins(ctx, notifications.KindDuplicatesResolved, notifications.Payload{
-			Count:  int64(res.Merged),
-			Detail: "Merged " + words.Count(res.Merged, "duplicate copy", "duplicate copies") + ".",
+			Count: int64(res.Merged), Items: mergedNames,
 		})
 	}
 	return res, nil