chore: remove dead code (packages, functions, types, constants)

Remove 5 unused packages (daemon, preview, proxy, workflow) and dead
symbols across 7 files: orchestrator workflow engine, skills Target type
and Update(), LSP config generation, installer SetupPrompt(), unexported
desktop options, and version License/Prerelease. Total: -1453 lines.

internal/installer/installer.go

@@ -290,46 +290,6 @@ func (i *Installer) installGit() InstallResult {
 	return InstallResult{Tool: "git", Success: true, Message: "installed and configured"}
 }
 
-func (i *Installer) SetupPrompt() error {
-	starshipPath, err := exec.LookPath("starship")
-	if err != nil {
-		return fmt.Errorf("starship not found")
-	}
-
-	rcFile := i.getRCFile()
-	line := fmt.Sprintf("eval \"$(" + starshipPath + " init %s)\"", i.system.Shell)
-	appendLine(rcFile, line)
-
-	configDir, _ := config.ConfigDir()
-	starshipConfig := `format = """
-$directory\
-$git_branch\
-$git_status\
-$git_metrics\
-$nodejs\
-$python\
-$golang\
-$rust\
-$cmd_duration\
-$line_break\
-$character"""
-
-[character]
-success_symbol = "[❯](bold green)"
-error_symbol = "[❯](bold red)"
-
-[git_branch]
-format = "[$symbol$branch]($style) "
-
-[git_status]
-format = '([$all_status$ahead_behind]($style) )'
-`
-	configPath := configDir + "/starship.toml"
-	os.MkdirAll(configDir, 0755)
-	os.WriteFile(configPath, []byte(starshipConfig), 0644)
-
-	return nil
-}
 
 func (i *Installer) getRCFile() string {
 	home, _ := os.UserHomeDir()