refactor: 项目结构重组，src/ 扁平化为根目录，提取 pkg/ 子包

- 模块名重命名 yunshu -> hub.gaomia.site/titor/YunShu
- Go 版本升级 1.21 -> 1.25
- src/ 目录删除，所有文件移至根目录
- 新增 pkg/mdprint/: Markdown AST 解析+ANSI 渲染
- 新增 pkg/style/: 终端颜色样式（8色 ANSI + 24位真彩色）
- 新增 pkg/termui/: 终端输入组件（交互式输入/密码/确认）
- 更新文档：AGENTS.md、architecture.md、changelog.md、taolun.md
- gitignore 通配符修复 yunshu.exe -> yunshu.exe*

pkg/style/style.go

@@ -0,0 +1,132 @@
+package style
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+var noColor = os.Getenv("NO_COLOR") != "" || os.Getenv("TERM") == "dumb"
+
+type Style struct {
+	codes []string
+}
+
+func New() *Style {
+	return &Style{}
+}
+
+func (s *Style) clone() *Style {
+	c := &Style{codes: make([]string, len(s.codes))}
+	copy(c.codes, s.codes)
+	return c
+}
+
+func (s *Style) Bold() *Style {
+	c := s.clone()
+	c.codes = append(c.codes, "1")
+	return c
+}
+
+func (s *Style) Dim() *Style {
+	c := s.clone()
+	c.codes = append(c.codes, "2")
+	return c
+}
+
+func (s *Style) Italic() *Style {
+	c := s.clone()
+	c.codes = append(c.codes, "3")
+	return c
+}
+
+func (s *Style) Underline() *Style {
+	c := s.clone()
+	c.codes = append(c.codes, "4")
+	return c
+}
+
+func (s *Style) Fg(c Color) *Style {
+	n := s.clone()
+	n.codes = append(n.codes, fmt.Sprintf("%d", c))
+	return n
+}
+
+func (s *Style) Bg(c Color) *Style {
+	n := s.clone()
+	n.codes = append(n.codes, fmt.Sprintf("%d", c+10))
+	return n
+}
+
+func (s *Style) FgHex(hex string) *Style {
+	n := s.clone()
+	r, g, b := hexToRGB(hex)
+	n.codes = append(n.codes, fmt.Sprintf("38;2;%d;%d;%d", r, g, b))
+	return n
+}
+
+func (s *Style) BgHex(hex string) *Style {
+	n := s.clone()
+	r, g, b := hexToRGB(hex)
+	n.codes = append(n.codes, fmt.Sprintf("48;2;%d;%d;%d", r, g, b))
+	return n
+}
+
+func hexToRGB(hex string) (r, g, b int) {
+	hex = strings.TrimPrefix(hex, "#")
+	if len(hex) != 6 {
+		return 255, 255, 255
+	}
+	r = parseHex(hex[0:2])
+	g = parseHex(hex[2:4])
+	b = parseHex(hex[4:6])
+	return
+}
+
+func parseHex(s string) int {
+	v := 0
+	for _, c := range s {
+		v *= 16
+		switch {
+		case c >= '0' && c <= '9':
+			v += int(c - '0')
+		case c >= 'a' && c <= 'f':
+			v += int(c - 'a' + 10)
+		case c >= 'A' && c <= 'F':
+			v += int(c - 'A' + 10)
+		}
+	}
+	return v
+}
+
+func (s *Style) Render(text string) string {
+	if noColor || len(s.codes) == 0 {
+		return text
+	}
+	return "\033[" + strings.Join(s.codes, ";") + "m" + text + "\033[0m"
+}
+
+type Color int
+
+const (
+	ColorBlack   Color = 30
+	ColorRed     Color = 31
+	ColorGreen   Color = 32
+	ColorYellow  Color = 33
+	ColorBlue    Color = 34
+	ColorMagenta Color = 35
+	ColorCyan    Color = 36
+	ColorWhite   Color = 37
+)
+
+var (
+	Red     = New().Fg(ColorRed)
+	Green   = New().Fg(ColorGreen)
+	Yellow  = New().Fg(ColorYellow)
+	Cyan    = New().Fg(ColorCyan)
+	Blue    = New().Fg(ColorBlue)
+	Magenta = New().Fg(ColorMagenta)
+	White   = New().Fg(ColorWhite)
+	Bold    = New().Bold()
+	Dim     = New().Dim()
+)