docs: improve CLI help, shell completion, and README

- Add command groups (Getting Started, Search, Downloads, Daemon, System)
- Add shell completion command (bash, zsh, fish, powershell)
- Add flag completions for --type, --quality, --sort, --lang, --genre,
  --country, --method, --player
- Improve Long descriptions and Examples for all commands
- Split doctor disk check into platform-specific files (Unix/Windows)
- Validate infoHash length before truncating (prevent panic)
- Fix references to non-existent 'unarr daemon start' command
- Move stats command to System & Diagnostics group
- Rewrite README with complete documentation, correct config format
  (toml not yaml), all commands, shell completion section

internal/cmd/root.go

@@ -28,7 +28,15 @@ func init() {
 		Long: `unarr is a powerful terminal tool for torrent search and management.
 
 Search 30+ torrent sources, inspect torrent quality, discover popular content,
-find streaming providers, and manage your media collection — all from your terminal.`,
+find streaming providers, and manage your media collection — all from your terminal.
+
+Get started:
+  unarr setup                          First-time configuration wizard
+  unarr search "breaking bad"          Search for content
+  unarr start                          Start the download daemon
+
+Documentation:  https://torrentclaw.com/cli
+Source:         https://github.com/torrentclaw/torrentclaw-cli`,
 		PersistentPreRun: func(cmd *cobra.Command, args []string) {
 			if noColor || os.Getenv("NO_COLOR") != "" {
 				color.NoColor = true
@@ -38,33 +46,95 @@ find streaming providers, and manage your media collection — all from your ter
 		SilenceErrors: true,
 	}
 
+	// Command groups for organized help output
+	rootCmd.AddGroup(
+		&cobra.Group{ID: "start", Title: "Getting Started:"},
+		&cobra.Group{ID: "search", Title: "Search & Discovery:"},
+		&cobra.Group{ID: "download", Title: "Downloads & Streaming:"},
+		&cobra.Group{ID: "daemon", Title: "Daemon Management:"},
+		&cobra.Group{ID: "system", Title: "System & Diagnostics:"},
+	)
+
 	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default ~/.config/unarr/config.toml)")
 	rootCmd.PersistentFlags().StringVar(&apiKeyFlag, "api-key", "", "API key (overrides config file and env)")
 	rootCmd.PersistentFlags().BoolVar(&jsonOut, "json", false, "output as JSON (for piping)")
 	rootCmd.PersistentFlags().BoolVar(&noColor, "no-color", false, "disable colored output")
 
+	// Getting Started
+	setupCmd := newSetupCmd()
+	setupCmd.GroupID = "start"
+	configCmd := newConfigCmd()
+	configCmd.GroupID = "start"
+
+	// Search & Discovery
+	searchCmd := newSearchCmd()
+	searchCmd.GroupID = "search"
+	inspectCmd := newInspectCmd()
+	inspectCmd.GroupID = "search"
+	popularCmd := newPopularCmd()
+	popularCmd.GroupID = "search"
+	recentCmd := newRecentCmd()
+	recentCmd.GroupID = "search"
+	watchCmd := newWatchCmd()
+	watchCmd.GroupID = "search"
+
+	// Downloads & Streaming
+	downloadCmd := newDownloadCmd()
+	downloadCmd.GroupID = "download"
+	streamCmd := newStreamCmd()
+	streamCmd.GroupID = "download"
+
+	// Daemon Management
+	startCmd := newStartCmd()
+	startCmd.GroupID = "daemon"
+	stopCmd := newStopCmd()
+	stopCmd.GroupID = "daemon"
+	statusCmd := newStatusCmd()
+	statusCmd.GroupID = "daemon"
+	daemonCmd := newDaemonCmd()
+	daemonCmd.GroupID = "daemon"
+
+	// System & Diagnostics
+	statsCmd := newStatsCmd()
+	statsCmd.GroupID = "system"
+	doctorCmd := newDoctorCmd()
+	doctorCmd.GroupID = "system"
+	selfUpdateCmd := newSelfUpdateCmd()
+	selfUpdateCmd.GroupID = "system"
+	versionCmd := newVersionCmd()
+	versionCmd.GroupID = "system"
+	completionCmd := newCompletionCmd()
+	completionCmd.GroupID = "system"
+
 	rootCmd.AddCommand(
-		newSetupCmd(),
-		newStartCmd(),
-		newStopCmd(),
-		newDaemonCmd(),
-		newDownloadCmd(),
-		newStatusCmd(),
-		newSearchCmd(),
-		newInspectCmd(),
-		newPopularCmd(),
-		newRecentCmd(),
-		newStatsCmd(),
-		newWatchCmd(),
-		newConfigCmd(),
-		newDoctorCmd(),
-		newVersionCmd(),
+		// Getting Started
+		setupCmd,
+		configCmd,
+		// Search & Discovery
+		searchCmd,
+		inspectCmd,
+		popularCmd,
+		recentCmd,
+		watchCmd,
+		// Downloads & Streaming
+		downloadCmd,
+		streamCmd,
+		// Daemon Management
+		startCmd,
+		stopCmd,
+		statusCmd,
+		daemonCmd,
+		// System & Diagnostics
+		statsCmd,
+		doctorCmd,
+		selfUpdateCmd,
+		versionCmd,
+		completionCmd,
 		// Stubs for future commands
 		newStubCmd("upgrade", "Find a better version of a torrent"),
 		newStubCmd("moreseed", "Find same quality with more seeders"),
 		newStubCmd("compare", "Compare two torrents side by side"),
 		newStubCmd("scan", "Scan your media library for upgrades"),
-		newStreamCmd(),
 		newStubCmd("add", "Search and add torrents to your client"),
 		newStubCmd("monitor", "Watch for new episodes of a series"),
 		newStubCmd("open", "Open content in the browser"),