refactor(office): generalize DataTable layout and document TUI table skill

Unify project/user flex column layout into layoutFlexTable with per-subject
policy in model. Add office-tui-table skill and AGENTS notes; fix CI go mod
tidy drift and test matrix Go version to match go.mod 1.25.

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

cmd/office/ui/table_layout_test.go

@@ -0,0 +1,49 @@
+package ui
+
+import (
+	"testing"
+
+	"github.com/eslider/go-onlyoffice/cmd/office/model"
+)
+
+func TestLayoutFlexTableAllProjectColumnsVisible(t *testing.T) {
+	cols := model.BuildColumns(model.SubjectProjects, nil)
+	flex, ok := model.TableFlexLayoutFor(model.SubjectProjects)
+	if !ok {
+		t.Fatal("expected flex layout for projects")
+	}
+	lay := layoutFlexTable(cols, 80, flex.FlexColumnKey, flex.MinFlexWidth)
+	if len(lay.indices) != 7 {
+		t.Fatalf("got %d visible columns, want 7", len(lay.indices))
+	}
+	sum := 0
+	for _, i := range lay.indices {
+		sum += lay.widths[i]
+	}
+	if sum != 80 {
+		t.Fatalf("width sum=%d want 80", sum)
+	}
+}
+
+func TestLayoutFlexTableUserEmailAbsorbsWidth(t *testing.T) {
+	cols := model.BuildColumns(model.SubjectUsers, nil)
+	flex, ok := model.TableFlexLayoutFor(model.SubjectUsers)
+	if !ok {
+		t.Fatal("expected flex layout for users")
+	}
+	lay := layoutFlexTable(cols, 100, flex.FlexColumnKey, flex.MinFlexWidth)
+	sum := 0
+	emailW := 0
+	for _, i := range lay.indices {
+		sum += lay.widths[i]
+		if cols[i].Key == "email" {
+			emailW = lay.widths[i]
+		}
+	}
+	if sum != 100 {
+		t.Fatalf("sum=%d want 100", sum)
+	}
+	if emailW < 20 {
+		t.Fatalf("email width=%d should absorb remainder", emailW)
+	}
+}