Replace manual prompt handling with console.ConfirmAction in trial command

[Copilot]

The trial command's confirmation prompt used manual fmt.Scanln handling instead of the standard console helper, creating inconsistency with other commands.

Changes

• Replaced fmt.Scanln with console.ConfirmAction in showTrialConfirmation function
• Removed manual response parsing and validation logic (~10 lines)
• Updated error handling to wrap ConfirmAction errors properly

Before:

fmt.Fprint(os.Stderr, console.FormatPromptMessage("Do you want to continue? [y/N]: "))
var response string
_, err := fmt.Scanln(&response)
if err != nil {
    response = "n"
}
response = strings.ToLower(strings.TrimSpace(response))
if response != "y" && response != "yes" {
    return fmt.Errorf("trial cancelled by user")
}

After:

confirmed, err := console.ConfirmAction(
    "Do you want to continue?",
    "Yes, proceed",
    "No, cancel",
)
if err != nil {
    return fmt.Errorf("confirmation failed: %w", err)
}
if !confirmed {
    return fmt.Errorf("trial cancelled by user")
}

This provides interactive Bubble Tea UI with automatic accessibility mode support, matching the pattern used in run_push.go.

Original prompt

Update trial command user interactive prompt to use console helpers instead

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