Use compact classification IDs and extend preview lifetime

internal/app/app_test.go

@@ -360,6 +360,65 @@ func TestPreviewIsReadOnlySelectedApplyPreservesFactsAndOtherFields(t *testing.T
 		t.Fatal("consumed preview applied twice")
 	}
 }
+
+func TestPreviewExpiresAfterTwentyFourHours(t *testing.T) {
+	for _, tc := range []struct {
+		name       string
+		age        time.Duration
+		newPreview bool
+		expired    bool
+	}{
+		{name: "apply before expiry", age: 24*time.Hour - time.Minute},
+		{name: "apply after expiry", age: 24*time.Hour + time.Minute, expired: true},
+		{name: "new preview retains unexpired review", age: 24*time.Hour - time.Minute, newPreview: true},
+		{name: "new preview discards expired review", age: 24*time.Hour + time.Minute, newPreview: true, expired: true},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			ctx := context.Background()
+			a, s := testApp(t)
+			s = seed(t, a, s)
+			mockClassifier(t, a)
+			p, err := runPreview(t, a, PreviewRequest{Revision: s.Revision, From: "2026-09-01", To: "2026-09-30", Model: "test/model", Fields: Fields{Category: true}})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if len(p.Changes) != 2 {
+				t.Fatalf("expected two proposed changes: %+v", p)
+			}
+			a.mu.Lock()
+			p.created = time.Now().Add(-tc.age)
+			a.previews[p.ID] = p
+			a.mu.Unlock()
+			if tc.newPreview {
+				// Completing another run performs expired-preview cleanup.
+				// An empty range needs no additional provider request.
+				if _, err := runPreview(t, a, PreviewRequest{Revision: s.Revision, From: "2025-01-01", To: "2025-01-31", Model: "test/model", Fields: Fields{Category: true}}); err != nil {
+					t.Fatal(err)
+				}
+			}
+			change := p.Changes[0]
+			_, err = a.ApplyPreview(ctx, p.ID, p.Revision, []string{change.ID}, nil)
+			if (err != nil) != tc.expired {
+				t.Fatalf("apply at age %s: error = %v, expired = %t", tc.age, err, tc.expired)
+			}
+			after, err := a.Snapshot(ctx)
+			if err != nil {
+				t.Fatal(err)
+			}
+			expected := domain.Clone(s.Data)
+			if !tc.expired {
+				for i := range expected.Transactions {
+					if expected.Transactions[i].Facts.ID == change.ID {
+						expected.Transactions[i].Enrichment = change.After
+					}
+				}
+			}
+			if !reflect.DeepEqual(after.Data, expected) {
+				t.Fatal("expiry handling did not preserve the expected transaction state")
+			}
+		})
+	}
+}
 func TestStalePreviewCannotOverwriteManualCorrection(t *testing.T) {
 	a, s := testApp(t)
 	s = seed(t, a, s)
@@ -491,7 +550,7 @@ func TestApplyPreviewHonoursReviewerEdits(t *testing.T) {
 func TestImportNeverAutoAppliesLowConfidenceCategory(t *testing.T) {
 	a, s := testApp(t)
 	provider := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		content := `{"merchant_id":null,"new_merchant":"REWE","category_id":"groceries","tag_ids":[],"confidence":"low"}`
+		content := `{"merchant_id":null,"new_merchant":"REWE","category_id":"c1","tag_ids":[],"confidence":"low"}`
 		json.NewEncoder(w).Encode(map[string]any{"choices": []any{map[string]any{
 			"finish_reason": "stop",
 			"message":       map[string]any{"content": content},

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 {