Fix vault creation to require mnemonic and set up initial unlocker

- Vault creation now prompts for mnemonic if not in environment
- Automatically creates passphrase unlocker during vault creation
- Prevents 'missing public key' error when adding secrets to new vaults
- Updates tests to reflect new vault creation flow

internal/cli/completion.go

@@ -0,0 +1,64 @@
+package cli
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+func newCompletionCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "completion [bash|zsh|fish|powershell]",
+		Short: "Generate completion script",
+		Long: `To load completions:
+
+Bash:
+  $ source <(secret completion bash)
+  # To load completions for each session, execute once:
+  # Linux:
+  $ secret completion bash > /etc/bash_completion.d/secret
+  # macOS:
+  $ secret completion bash > $(brew --prefix)/etc/bash_completion.d/secret
+
+Zsh:
+  # If shell completion is not already enabled in your environment,
+  # you will need to enable it.  You can execute the following once:
+  $ echo "autoload -U compinit; compinit" >> ~/.zshrc
+
+  # To load completions for each session, execute once:
+  $ secret completion zsh > "${fpath[1]}/_secret"
+  # You will need to start a new shell for this setup to take effect.
+
+Fish:
+  $ secret completion fish | source
+  # To load completions for each session, execute once:
+  $ secret completion fish > ~/.config/fish/completions/secret.fish
+
+PowerShell:
+  PS> secret completion powershell | Out-String | Invoke-Expression
+  # To load completions for every new session, run:
+  PS> secret completion powershell > secret.ps1
+  # and source this file from your PowerShell profile.
+`,
+		DisableFlagsInUseLine: true,
+		ValidArgs:             []string{"bash", "zsh", "fish", "powershell"},
+		Args:                  cobra.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			switch args[0] {
+			case "bash":
+				return cmd.Root().GenBashCompletion(os.Stdout)
+			case "zsh":
+				return cmd.Root().GenZshCompletion(os.Stdout)
+			case "fish":
+				return cmd.Root().GenFishCompletion(os.Stdout, true)
+			case "powershell":
+				return cmd.Root().GenPowerShellCompletionWithDesc(os.Stdout)
+			default:
+				return fmt.Errorf("unsupported shell type: %s", args[0])
+			}
+		},
+	}
+
+	return cmd
+}