feat(office): add Workspace TUI with shared bootstrap and test suite

Introduce the office Bubble Tea browser (module tree, multi-select lists,
markdown preview) alongside oo, with cmd/internal/bootstrap for shared auth,
unit tests across preview/model/ui/fetch, CI build for both binaries, and
GoReleaser archives for office.

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

cmd/office/fetch/fetch_integration_test.go

@@ -0,0 +1,45 @@
+//go:build integration
+
+package fetch_test
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/eslider/go-onlyoffice/cmd/internal/bootstrap"
+	"github.com/eslider/go-onlyoffice/cmd/office/fetch"
+	"github.com/eslider/go-onlyoffice/cmd/office/model"
+)
+
+func TestIntegrationListProjects(t *testing.T) {
+	if os.Getenv("ONLYOFFICE_URL") == "" && os.Getenv("ONLYOFFICE_HOST") == "" {
+		t.Skip("ONLYOFFICE_URL not set")
+	}
+	client, err := bootstrap.NewClient(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	loader := &fetch.Loader{Client: client}
+	items, err := loader.List(context.Background(), model.SubjectProjects)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("projects: %d", len(items))
+}
+
+func TestIntegrationListMailInbox(t *testing.T) {
+	if os.Getenv("ONLYOFFICE_URL") == "" && os.Getenv("ONLYOFFICE_HOST") == "" {
+		t.Skip("ONLYOFFICE_URL not set")
+	}
+	client, err := bootstrap.NewClient(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	loader := &fetch.Loader{Client: client}
+	items, err := loader.List(context.Background(), model.SubjectMailInbox)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("mail messages: %d", len(items))
+}