feat(office): table detail panes and Alt+1/2/3 layout toggles

Add spreadsheet-style list, split detail pane with forms and document preview,
and Alt+1/2/3 to show/hide panes with even width distribution.

Co-authored-by: Cursor <cursoragent@cursor.com>

cmd/office/fetch/save.go

@@ -0,0 +1,43 @@
+package fetch
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+
+	onlyoffice "github.com/eslider/go-onlyoffice"
+	"github.com/eslider/go-onlyoffice/cmd/office/model"
+)
+
+// SaveItem persists editable form fields for supported entity kinds.
+func (l *Loader) SaveItem(ctx context.Context, item model.Item, title, description string) error {
+	if l == nil || l.Client == nil {
+		return fmt.Errorf("fetch: client is nil")
+	}
+	switch item.Kind {
+	case model.KindTask:
+		return l.UpdateTask(ctx, item.ID, title, description)
+	case model.KindProject:
+		id, err := strconv.Atoi(item.ID)
+		if err != nil {
+			return err
+		}
+		_, err = l.Client.UpdateProject(onlyoffice.ProjectUpdateRequest{
+			ID:          id,
+			Title:       title,
+			Description: description,
+		})
+		return err
+	default:
+		return fmt.Errorf("save not supported for %s", item.Kind)
+	}
+}
+
+// DetailForm loads form field values for the detail pane.
+func (l *Loader) DetailForm(ctx context.Context, item model.Item) (model.FormFields, error) {
+	raw, err := l.Detail(ctx, item)
+	if err != nil {
+		return model.FormFields{}, err
+	}
+	return model.FormFieldsFromRaw(item.Kind, raw), nil
+}