enhance skill installer (#1252)

* enhance skill installer

* enhance install skills v2

* go file formate

* fix:use proxy download skills;many chunck download;simple code

* add default config to config.example.json, download skill from github use proxy and token

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Co-authored-by: FantasticCode2019 <1443996278@qq.com>

cmd/picoclaw/internal/skills/command.go

@@ -29,7 +29,15 @@ func NewSkillsCommand() *cobra.Command {
 			}
 
 			d.workspace = cfg.WorkspacePath()
-			d.installer = skills.NewSkillInstaller(d.workspace)
+			installer, err := skills.NewSkillInstaller(
+				d.workspace,
+				cfg.Tools.Skills.Github.Token,
+				cfg.Tools.Skills.Github.Proxy,
+			)
+			if err != nil {
+				return fmt.Errorf("error creating skills installer: %w", err)
+			}
+			d.installer = installer
 
 			// get global config directory and builtin skills directory
 			globalDir := filepath.Dir(internal.GetConfigPath())