feat: Add ask update command and version pinning

- Add cmd/update.go: Update one or all installed skills
- Add version pinning: ask install skill@v1.0.0
- Update SPEC.md with completed features
- Update task.md with progress

Author: yeasy

SPEC.md

@@ -20,16 +20,16 @@ ASK 是一个用于管理 AI Agent 技能的命令行工具，类似于 Homebrew
 | `ask init` | 初始化项目，创建 `ask.yaml` | ✅ |
 | `ask search <keyword>` | 搜索技能（并行多源） | ✅ |
 | `ask install <skill>` | 安装技能 | ✅ |
+| `ask install skill@v1.0` | 版本锁定安装 | ✅ |
 | `ask uninstall <skill>` | 卸载技能 | ✅ |
 | `ask list` | 列出已安装技能 | ✅ |
 | `ask info <skill>` | 显示技能详情 | ✅ |
+| `ask update [skill]` | 更新技能到最新版本 | ✅ |
 
 ### 待实现功能 ⏳
 
 | 命令 | 功能 | 优先级 |
 |------|------|--------|
-| `ask update [skill]` | 更新技能到最新版本 | P1 |
-| `ask install skill@v1.0` | 版本锁定安装 | P1 |
 | `ask create <name>` | 创建技能模板 | P2 |
 
 ---
@@ -58,6 +58,14 @@ sources:
     url: modelcontextprotocol/servers/src
 ```
 
+### 可添加的来源（待验证）
+
+| 来源 | URL | 说明 |
+|------|-----|------|
+| OpenAI Skills | `openai/skills/skills` | OpenAI Codex 官方技能 |
+| GitHub Copilot | `github/awesome-copilot/skills` | GitHub Copilot 技能 |
+| SkillsMP | skillsmp.com | 技能市场（需API） |
+
 ---
 
 ## SKILL.md 规范
@@ -184,8 +192,8 @@ ask/
 ## 待办事项
 
 ### 高优先级 (P1)
-- [ ] `ask update` 命令
-- [ ] 版本锁定 (`skill@v1.0`)
+- [x] `ask update` 命令
+- [x] 版本锁定 (`skill@v1.0`)
 - [ ] Homebrew tap 仓库创建
 
 ### 中优先级 (P2)

cmd/install.go

@@ -17,11 +17,19 @@ var installCmd = &cobra.Command{
 	Use:   "install [url]",
 	Short: "Install a skill from a git repository",
 	Long: `Download and install a skill into the ./skills directory. 
-You can provide a full git URL or a GitHub shorthand (owner/repo).`,
+You can provide a full git URL or a GitHub shorthand (owner/repo).
+You can also specify a version: owner/repo@v1.0.0`,
 	Args: cobra.ExactArgs(1),
 	Run: func(cmd *cobra.Command, args []string) {
 		input := args[0]
 
+		// Parse version if specified (skill@version)
+		var version string
+		if idx := strings.LastIndex(input, "@"); idx != -1 && !strings.HasPrefix(input, "git@") {
+			version = input[idx+1:]
+			input = input[:idx]
+		}
+
 		// Check if it's a direct URL or shorthand
 		isURL := strings.HasPrefix(input, "http") || strings.HasPrefix(input, "git@")
 
@@ -70,6 +78,14 @@ You can provide a full git URL or a GitHub shorthand (owner/repo).`,
 			os.Exit(1)
 		}
 
+		// Checkout specific version if specified
+		if version != "" && subDir == "" {
+			fmt.Printf("Checking out version %s...\n", version)
+			if err := git.Checkout(destPath, version); err != nil {
+				fmt.Printf("Warning: Failed to checkout version %s: %v\n", version, err)
+			}
+		}
+
 		// Update config
 		cfg, err := config.LoadConfig()
 		if err == nil {

cmd/update.go

@@ -0,0 +1,87 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+	"github.com/yeasy/ask/internal/config"
+)
+
+// updateCmd represents the update command
+var updateCmd = &cobra.Command{
+	Use:   "update [skill-name]",
+	Short: "Update installed skills to latest version",
+	Long: `Update one or all installed skills to their latest versions.
+If no skill name is provided, updates all installed skills.`,
+	Run: func(cmd *cobra.Command, args []string) {
+		cfg, err := config.LoadConfig()
+		if err != nil {
+			if os.IsNotExist(err) {
+				fmt.Println("No ask.yaml found. Run 'ask init' first.")
+				return
+			}
+			fmt.Printf("Error loading config: %v\n", err)
+			os.Exit(1)
+		}
+
+		if len(cfg.Skills) == 0 {
+			fmt.Println("No skills installed.")
+			return
+		}
+
+		// Determine which skills to update
+		var skillsToUpdate []string
+		if len(args) > 0 {
+			// Update specific skill
+			skillName := args[0]
+			found := false
+			for _, s := range cfg.Skills {
+				if s == skillName {
+					found = true
+					break
+				}
+			}
+			if !found {
+				fmt.Printf("Skill '%s' is not installed.\n", skillName)
+				os.Exit(1)
+			}
+			skillsToUpdate = []string{skillName}
+		} else {
+			// Update all skills
+			skillsToUpdate = cfg.Skills
+		}
+
+		for _, skillName := range skillsToUpdate {
+			skillPath := filepath.Join("skills", skillName)
+
+			// Check if it's a git repository
+			gitDir := filepath.Join(skillPath, ".git")
+			if _, err := os.Stat(gitDir); os.IsNotExist(err) {
+				fmt.Printf("Skipping %s (not a git repository)\n", skillName)
+				continue
+			}
+
+			fmt.Printf("Updating %s...\n", skillName)
+
+			// Run git pull
+			gitCmd := exec.Command("git", "pull", "--rebase")
+			gitCmd.Dir = skillPath
+			gitCmd.Stdout = os.Stdout
+			gitCmd.Stderr = os.Stderr
+
+			if err := gitCmd.Run(); err != nil {
+				fmt.Printf("  Failed to update %s: %v\n", skillName, err)
+				continue
+			}
+
+			fmt.Printf("  Updated %s successfully!\n", skillName)
+		}
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(updateCmd)
+}