fix: completion install writes non-empty scripts

GenBashCompletionV2/GenZshCompletion/GenFishCompletion write into the
buffer as a side effect; capturing buf.String() in the return statement
before the Gen* call runs means the buffer is always empty. Separate
the call from the return to fix evaluation order.

Also call InitDefaultCompletionCmd() before iterating root.Commands()
so the lazily-initialized completion subtree is visible before Execute().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cmd/netssh/main.go

@@ -208,9 +208,10 @@ func rootCmd() *cobra.Command {
 		},
 	}
 
-	// cobra automatically adds a "completion" subcommand; we extend it with "install".
 	root.AddCommand(configureCmd(), searchCmd(), cacheCmd())
 
+	// cobra builds the "completion" command lazily; force init so we can extend it.
+	root.InitDefaultCompletionCmd()
 	for _, cmd := range root.Commands() {
 		if cmd.Name() == "completion" {
 			cmd.AddCommand(completionInstallCmd(root))
@@ -244,7 +245,8 @@ func completionInstallCmd(root *cobra.Command) *cobra.Command {
 				file = filepath.Join(dir, "netssh")
 				gen = func() ([]byte, error) {
 					var buf strings.Builder
-					return []byte(buf.String()), root.GenBashCompletionV2(&buf, true)
+					err := root.GenBashCompletionV2(&buf, true)
+					return []byte(buf.String()), err
 				}
 				note = "Reload your shell or run: source " + file
 			case "zsh":
@@ -252,7 +254,8 @@ func completionInstallCmd(root *cobra.Command) *cobra.Command {
 				file = filepath.Join(dir, "_netssh")
 				gen = func() ([]byte, error) {
 					var buf strings.Builder
-					return []byte(buf.String()), root.GenZshCompletion(&buf)
+					err := root.GenZshCompletion(&buf)
+					return []byte(buf.String()), err
 				}
 				note = "Make sure ~/.zfunc is in your fpath:\n  fpath=(~/.zfunc $fpath)\n  autoload -Uz compinit && compinit"
 			case "fish":
@@ -261,7 +264,8 @@ func completionInstallCmd(root *cobra.Command) *cobra.Command {
 				file = filepath.Join(dir, "netssh.fish")
 				gen = func() ([]byte, error) {
 					var buf strings.Builder
-					return []byte(buf.String()), root.GenFishCompletion(&buf, true)
+					err := root.GenFishCompletion(&buf, true)
+					return []byte(buf.String()), err
 				}
 				note = "Reload your shell or start a new fish session."
 			default: