Let reviews see low-confidence suggestions and rebase preview applies

A low-confidence answer was discarded inside Classify, so Analyse showed
the row as unchanged instead of a reviewable suggestion; the fallback
decision moves to the import path, which keeps the merchant link and the
recorded confidence. ApplyPreview now rebases onto the current journal:
unrelated commits during a minutes-long paced run no longer invalidate
the review, only an edit to a selected transaction itself conflicts, and
applied changes are pruned so the rest stay appliable.

internal/app/app_test.go

@@ -369,6 +369,82 @@ func TestStalePreviewCannotOverwriteManualCorrection(t *testing.T) {
 		t.Fatal("stale apply partially changed records")
 	}
 }
+
+// A preview run is minutes long by design (paced provider calls), so a
+// scheduled sync, an import, or an earlier partial apply committing in the
+// meantime must not invalidate the review: only an edit to a selected
+// transaction itself conflicts.
+func TestApplyPreviewSurvivesUnrelatedCommitsAndPartialApplies(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)
+	}
+	// An unrelated registry edit moves the journal revision after the preview.
+	if _, err = a.Mutate(ctx, s.Revision, func(d *domain.Dataset) error {
+		d.Tags = append(d.Tags, domain.Tag{ID: "travel", Name: "travel"})
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+	first, err := a.ApplyPreview(ctx, p.ID, p.Revision, []string{p.Changes[0].ID})
+	if err != nil {
+		t.Fatalf("unrelated commit invalidated the preview: %v", err)
+	}
+	// The partial apply moved the revision again; the remaining proposal must
+	// still apply without another paced provider run.
+	second, err := a.ApplyPreview(ctx, p.ID, p.Revision, []string{p.Changes[1].ID})
+	if err != nil {
+		t.Fatalf("partial apply consumed the remaining proposals: %v", err)
+	}
+	if second.Revision == first.Revision {
+		t.Fatal("second apply committed nothing")
+	}
+	for _, tx := range second.Data.Transactions {
+		if tx.Enrichment.CategoryID != "groceries" {
+			t.Fatalf("applied categories lost: %+v", tx.Enrichment)
+		}
+	}
+	// Both changes are consumed now; re-applying must fail, not double-write.
+	if _, err = a.ApplyPreview(ctx, p.ID, p.Revision, []string{p.Changes[0].ID}); err == nil {
+		t.Fatal("consumed change applied twice")
+	}
+}
+
+// Imports auto-apply only what the model is sure about: a low-confidence
+// category lands on the editable fallback while the merchant link and the
+// recorded confidence survive for review in Analyse.
+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"}`
+		json.NewEncoder(w).Encode(map[string]any{"choices": []any{map[string]any{
+			"finish_reason": "stop",
+			"message":       map[string]any{"content": content},
+		}}})
+	}))
+	defer provider.Close()
+	a.classifier = classification.Client{APIKey: "test", Model: "test/model", BaseURL: provider.URL}
+	s = seed(t, a, s)
+	if len(s.Data.Transactions) != 2 {
+		t.Fatalf("import lost transactions: %d", len(s.Data.Transactions))
+	}
+	for _, tx := range s.Data.Transactions {
+		e := tx.Enrichment
+		if e.CategoryID != domain.ExpenseFallback {
+			t.Fatalf("low-confidence category was auto-applied: %+v", e)
+		}
+		if e.MerchantID == "" || e.Classification.Confidence != "low" || e.Classification.Source != "openrouter" {
+			t.Fatalf("merchant link or provenance lost: %+v", e)
+		}
+	}
+}
 func TestTaxonomyProposalApprovalMintsOnlyApprovedEntries(t *testing.T) {
 	a, s := testApp(t)
 	s = seed(t, a, s)