fix: net ports 表格按显示宽度对齐，修正中文表头导致的错位

text/tabwriter 按字节数计算列宽，中文表头每个字 3 字节但只占 2 列，
导致表头下方的数据列整体错位。改为自行计算终端显示宽度（CJK 算 2 列）
补空格，行尾不留空白；监听地址 0.0.0.0/:: 统一显示为 *。

internal/executor/netports.go

@@ -9,7 +9,6 @@ import (
 	"sort"
 	"strconv"
 	"strings"
-	"text/tabwriter"
 )
 
 // listeningPort is one listening socket with its owner, normalised across
@@ -71,6 +70,10 @@ func runNetPorts(ctx context.Context, req BuiltinRequest) error {
 }
 
 // renderListeningPorts writes the table, sorted by port.
+//
+// text/tabwriter measures in bytes, which misaligns the CJK headings (each
+// character is three bytes wide but only two columns on screen), so the
+// columns are padded by display width instead.
 func renderListeningPorts(ports []listeningPort, req BuiltinRequest) {
 	if len(ports) == 0 {
 		if req.Stderr != nil {
@@ -79,19 +82,87 @@ func renderListeningPorts(ports []listeningPort, req BuiltinRequest) {
 		return
 	}
 
-	tw := tabwriter.NewWriter(req.Stdout, 0, 0, 2, ' ', 0)
-	fmt.Fprintln(tw, "端口\t协议\t地址\tPID\t进程")
+	rows := [][]string{{"端口", "协议", "地址", "PID", "进程"}}
 	for _, p := range ports {
 		pid, process := p.PID, p.Process
 		if pid == "" {
-			pid, process = "-", "-"
+			pid = "-"
 		}
 		if process == "" {
 			process = "-"
 		}
-		fmt.Fprintf(tw, "%d\t%s\t%s\t%s\t%s\n", p.Port, p.Proto, p.Address, pid, process)
+		rows = append(rows, []string{
+			strconv.Itoa(p.Port), p.Proto, displayAddress(p.Address), pid, process,
+		})
 	}
-	_ = tw.Flush()
+
+	// The last column is not padded, so lines end without trailing spaces.
+	widths := make([]int, len(rows[0]))
+	for _, row := range rows {
+		for i, cell := range row {
+			if w := displayWidth(cell); w > widths[i] {
+				widths[i] = w
+			}
+		}
+	}
+
+	// Two spaces between columns, as the rest of kopsc's tables use.
+	const gap = 2
+	var b strings.Builder
+	for _, row := range rows {
+		b.Reset()
+		for i, cell := range row {
+			b.WriteString(cell)
+			if i < len(row)-1 {
+				b.WriteString(strings.Repeat(" ", widths[i]-displayWidth(cell)+gap))
+			}
+		}
+		fmt.Fprintln(req.Stdout, strings.TrimRight(b.String(), " "))
+	}
+}
+
+// displayAddress shows a listening address the way ss/netstat print it: a
+// wildcard bind is "*", an IPv6 wildcard is "::".
+func displayAddress(addr string) string {
+	switch addr {
+	case "", "0.0.0.0", "::":
+		return "*"
+	}
+	return addr
+}
+
+// displayWidth counts the columns a string occupies in a terminal: two for
+// wide (CJK) runes, one otherwise. Combining marks are ignored.
+func displayWidth(s string) int {
+	width := 0
+	for _, r := range s {
+		width += runeWidth(r)
+	}
+	return width
+}
+
+// runeWidth is the usual wcwidth approximation: East Asian wide characters
+// take two columns, everything else one.
+func runeWidth(r rune) int {
+	switch {
+	case r == 0:
+		return 0
+	case r < 32:
+		return 0
+	case r < 0x1100:
+		return 1
+	case r <= 0x115F, // Hangul Jamo
+		r >= 0x2E80 && r <= 0xA4CF, // CJK radicals, Kana, CJK ideographs
+		r >= 0xAC00 && r <= 0xD7A3, // Hangul syllables
+		r >= 0xF900 && r <= 0xFAFF, // CJK compatibility ideographs
+		r >= 0xFE30 && r <= 0xFE6F, // CJK compatibility forms
+		r >= 0xFF00 && r <= 0xFF60, // fullwidth forms
+		r >= 0xFFE0 && r <= 0xFFE6,
+		r >= 0x1F300 && r <= 0x1F64F, // emoji
+		r >= 0x20000 && r <= 0x3FFFD:
+		return 2
+	}
+	return 1
 }
 
 // listenCommandFor picks the platform's command.

internal/executor/netports_test.go

@@ -218,3 +218,75 @@ func TestNetPortsRawKeepsCommandOutput(t *testing.T) {
 func strconvQuote(s string) string {
 	return "'" + strings.ReplaceAll(s, "'", `'\''`) + "'"
 }
+
+func TestDisplayWidth(t *testing.T) {
+	cases := map[string]int{
+		"端口":        4, // each CJK rune is two columns
+		"PID":       3,
+		"127.0.0.1": 9,
+		"进程":        4,
+		"":          0,
+	}
+	for in, want := range cases {
+		if got := displayWidth(in); got != want {
+			t.Errorf("displayWidth(%q) = %d, want %d", in, got, want)
+		}
+	}
+}
+
+// TestRenderListeningPortsAlignsCJKHeader guards the alignment bug: with the
+// old byte-based tabwriter the CJK headings pushed every data column, because
+// each heading rune counts as three bytes but only two columns.
+func TestRenderListeningPortsAlignsCJKHeader(t *testing.T) {
+	ports := []listeningPort{
+		{Proto: "TCP", Address: "127.0.0.1", Port: 22, PID: "901", Process: "sshd"},
+		{Proto: "TCP", Address: "0.0.0.0", Port: 3306, PID: "2442", Process: "docker"},
+	}
+	var out bytes.Buffer
+	renderListeningPorts(ports, BuiltinRequest{Stdout: &out, Stderr: &out})
+
+	lines := strings.Split(strings.TrimRight(out.String(), "\n"), "\n")
+	if len(lines) != 3 {
+		t.Fatalf("expected header + 2 rows, got %d:\n%s", len(lines), out.String())
+	}
+
+	// "协议" is the heading above the "TCP" column, so that cell must start at
+	// the same display column on every line — the bug put it further right.
+	want := columnStart(lines[0], "协议")
+	for i, line := range lines[1:] {
+		if got := columnStart(line, "TCP"); got != want {
+			t.Errorf("row %d: TCP starts at display column %d, header 协议 at %d:\n%s",
+				i+1, got, want, out.String())
+		}
+	}
+
+	for _, line := range lines {
+		if line != strings.TrimRight(line, " ") {
+			t.Errorf("trailing spaces in %q", line)
+		}
+	}
+}
+
+// columnStart returns the display column at which cell begins in line.
+func columnStart(line, cell string) int {
+	i := strings.Index(line, cell)
+	if i < 0 {
+		return -1
+	}
+	return displayWidth(line[:i])
+}
+
+func TestDisplayAddress(t *testing.T) {
+	cases := map[string]string{
+		"0.0.0.0":   "*",
+		"::":        "*",
+		"":          "*",
+		"127.0.0.1": "127.0.0.1",
+		"::1":       "::1",
+	}
+	for in, want := range cases {
+		if got := displayAddress(in); got != want {
+			t.Errorf("displayAddress(%q) = %q, want %q", in, got, want)
+		}
+	}
+}