fix(output): 表头取所有行字段并集并固定核心列顺序

printSliceTable 原先只从第一行取表头，导致列时有时无；改为取所有行并集。新增 protected/last_commit/commit_time 到优先表头，固定分支核心列顺序。

internal/output/formatter.go

@@ -150,15 +150,19 @@ func printSliceTable(w io.Writer, items []interface{}) error {
 		return nil
 	}
 
-	// Collect headers from first item
-	first, ok := items[0].(map[string]interface{})
-	if !ok {
+	// If the first item isn't a map, fall back to JSON (unchanged behavior).
+	if _, ok := items[0].(map[string]interface{}); !ok {
 		data, _ := json.MarshalIndent(items, "", "  ")
 		fmt.Fprintln(w, string(data))
 		return nil
 	}
 
-	headers := collectKeys(first)
+	// Headers are the UNION of every row's keys, so a column appears whenever
+	// any row carries the field. GitLink payloads (e.g. branch lists) do not
+	// always include every key on every item; taking headers from items[0]
+	// alone made columns like `protected` appear or vanish depending on which
+	// item happened to rank first.
+	headers := collectKeysUnion(items)
 	omitted := 0
 	if len(headers) > maxTableColumns {
 		omitted = len(headers) - maxTableColumns
@@ -240,20 +244,24 @@ func writeMapRow(tw *tabwriter.Writer, key string, v interface{}, depth int) {
 // columns a user actually scans.
 var preferredHeaders = []string{
 	"id", "name", "login", "title", "subject", "number",
-	"status", "state", "type", "time_ago", "created_time",
-	"created_at", "updated_at",
+	"status", "state", "protected", "last_commit", "commit_time",
+	"type", "time_ago", "created_time", "created_at", "updated_at",
 }
 
-func collectKeys(m map[string]interface{}) []string {
-	keys := make([]string, 0, len(m))
+// orderKeySet returns the keys of keySet ordered by preferredHeaders: priority
+// fields come first in their defined order, the rest follow in set-iteration
+// order. Keys absent from preferredHeaders still appear, just after the
+// priority fields.
+func orderKeySet(keySet map[string]bool) []string {
+	keys := make([]string, 0, len(keySet))
 	seen := map[string]bool{}
-	for _, k := range preferredHeaders {
-		if _, ok := m[k]; ok {
-			keys = append(keys, k)
-			seen[k] = true
+	for _, p := range preferredHeaders {
+		if keySet[p] {
+			keys = append(keys, p)
+			seen[p] = true
 		}
 	}
-	for k := range m {
+	for k := range keySet {
 		if !seen[k] {
 			keys = append(keys, k)
 		}
@@ -261,6 +269,32 @@ func collectKeys(m map[string]interface{}) []string {
 	return keys
 }
 
+// collectKeysUnion merges the keys of every map in items into a single
+// priority-ordered header list. Used by printSliceTable so a column shows
+// whenever any row has the field — preventing columns from disappearing when
+// the first row happens to omit a key (e.g. `protected` on GitLink branches).
+func collectKeysUnion(items []interface{}) []string {
+	keySet := map[string]bool{}
+	for _, it := range items {
+		m, ok := it.(map[string]interface{})
+		if !ok {
+			continue
+		}
+		for k := range m {
+			keySet[k] = true
+		}
+	}
+	return orderKeySet(keySet)
+}
+
+func collectKeys(m map[string]interface{}) []string {
+	keySet := make(map[string]bool, len(m))
+	for k := range m {
+		keySet[k] = true
+	}
+	return orderKeySet(keySet)
+}
+
 func formatValue(v interface{}) string {
 	if v == nil {
 		return ""

internal/output/formatter_test.go

@@ -305,3 +305,64 @@ func TestFormatNestedMap_LoginAndSha(t *testing.T) {
 		t.Errorf("expected sha to be truncated, got %q", got)
 	}
 }
+
+// TestPrintSliceTable_HeaderUnionAcrossRows 验证当各行字段集合不一致时
+// （GitLink 分支列表的典型情况：并非每个分支都返回 protected 字段），
+// 表头应取所有行的字段并集，而不是仅取第一行。否则 protected 列会因落在
+// 第一位的样本恰好缺失而「时有时无」。
+func TestPrintSliceTable_HeaderUnionAcrossRows(t *testing.T) {
+	items := []interface{}{
+		map[string]interface{}{"name": "develop"},                  // 第一行缺 protected
+		map[string]interface{}{"name": "main", "protected": false}, // 第二行带 protected
+	}
+	var buf bytes.Buffer
+	if err := printSliceTable(&buf, items); err != nil {
+		t.Fatalf("printSliceTable returned error: %v", err)
+	}
+	out := buf.String()
+	if !strings.Contains(out, "protected") {
+		t.Errorf("expected header to include \"protected\" from row union (not just first row); got:\n%s", out)
+	}
+	if !strings.Contains(out, "develop") || !strings.Contains(out, "main") {
+		t.Errorf("expected both rows present in output; got:\n%s", out)
+	}
+}
+
+// TestPrintSliceTable_ProtectedSurvivesColumnCap 验证当列数超过上限时，
+// protected（是否保护分支）作为优先字段会被保留、不被截断丢弃——否则在
+// 字段较多的分支列表里这一列仍可能消失。
+func TestPrintSliceTable_ProtectedSurvivesColumnCap(t *testing.T) {
+	row := map[string]interface{}{}
+	cols := []string{"a1", "a2", "a3", "a4", "a5", "a6", "a7", "a8", "id", "name", "protected"}
+	for _, c := range cols {
+		row[c] = "v"
+	}
+	var buf bytes.Buffer
+	if err := printSliceTable(&buf, []interface{}{row}); err != nil {
+		t.Fatalf("printSliceTable returned error: %v", err)
+	}
+	out := buf.String()
+	if !strings.Contains(out, "protected") {
+		t.Errorf("expected priority field \"protected\" to survive the column cap; got:\n%s", out)
+	}
+}
+
+// TestOrderKeySet_BranchColumnOrderIsStable 守护分支核心列的固定顺序
+// name / protected / last_commit / commit_time。当前若 last_commit /
+// commit_time 不在 preferredHeaders，orderKeySet 会把这两个非优先键按 map
+// 遍历序追加，导致列顺序随机——重复调用必暴露不一致。
+func TestOrderKeySet_BranchColumnOrderIsStable(t *testing.T) {
+	want := []string{"name", "protected", "last_commit", "commit_time"}
+	keys := map[string]bool{"name": true, "protected": true, "last_commit": true, "commit_time": true}
+	for i := 0; i < 100; i++ {
+		got := orderKeySet(keys)
+		if len(got) != len(want) {
+			t.Fatalf("iteration %d: got %d keys %v, want %v", i, len(got), got, want)
+		}
+		for j, w := range want {
+			if got[j] != w {
+				t.Fatalf("iteration %d: got[%d]=%q, want %q (full %v)", i, j, got[j], w, got)
+			}
+		}
+	}
+}