feat(help): add CLI help command

Adds internal/cmd/help which provides enhanced help functionality.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/cmd/help/cmd.go

@@ -0,0 +1,66 @@
+package help
+
+import (
+	"fmt"
+
+	"github.com/host-uk/core/pkg/cli"
+	"github.com/host-uk/core/pkg/help"
+)
+
+func init() {
+	cli.RegisterCommands(AddHelpCommands)
+}
+
+func AddHelpCommands(root *cli.Command) {
+	var searchFlag string
+
+	helpCmd := &cli.Command{
+		Use:   "help [topic]",
+		Short: "Display help documentation",
+		Run: func(cmd *cli.Command, args []string) {
+			catalog := help.DefaultCatalog()
+
+			if searchFlag != "" {
+				results := catalog.Search(searchFlag)
+				if len(results) == 0 {
+					fmt.Println("No topics found.")
+					return
+				}
+				fmt.Println("Search Results:")
+				for _, res := range results {
+					fmt.Printf("  %s - %s\n", res.Topic.ID, res.Topic.Title)
+				}
+				return
+			}
+
+			if len(args) == 0 {
+				topics := catalog.List()
+				fmt.Println("Available Help Topics:")
+				for _, t := range topics {
+					fmt.Printf("  %s - %s\n", t.ID, t.Title)
+				}
+				return
+			}
+
+			topic, err := catalog.Get(args[0])
+			if err != nil {
+				fmt.Printf("Error: %v\n", err)
+				return
+			}
+
+			renderTopic(topic)
+		},
+	}
+
+	helpCmd.Flags().StringVarP(&searchFlag, "search", "s", "", "Search help topics")
+	root.AddCommand(helpCmd)
+}
+
+func renderTopic(t *help.Topic) {
+	// Simple ANSI rendering for now
+	// Use explicit ANSI codes or just print
+	fmt.Printf("\n\033[1;34m%s\033[0m\n", t.Title) // Blue bold title
+	fmt.Println("----------------------------------------")
+	fmt.Println(t.Content)
+	fmt.Println()
+}