Use compact classification IDs and extend preview lifetime

internal/app/reclassify.go

@@ -13,6 +13,8 @@ import (
 	"finance-duck/internal/domain"
 )
 
+const previewLifetime = 24 * time.Hour
+
 type Fields struct {
 	Merchant bool `json:"merchant"`
 	Category bool `json:"category"`
@@ -173,7 +175,7 @@ func (a *App) runPreview(ctx context.Context, cancel context.CancelFunc, client
 		return
 	}
 	for id, old := range a.previews {
-		if time.Since(old.created) > time.Hour {
+		if time.Since(old.created) > previewLifetime {
 			delete(a.previews, id)
 		}
 	}
@@ -343,7 +345,7 @@ func (a *App) ApplyPreview(ctx context.Context, id, rev string, ids []string, ed
 	a.mu.Lock()
 	defer a.mu.Unlock()
 	p, ok := a.previews[id]
-	if !ok || time.Since(p.created) > time.Hour {
+	if !ok || time.Since(p.created) > previewLifetime {
 		return State{}, errors.New("preview expired or unknown; analyse again")
 	}
 	if rev != p.Revision {