feat: add stacked layout to odyssey_toggle_button

[coladarci]

Summary

• Adds a layout attr to odyssey_toggle_button — :inline (default, existing behavior unchanged) or :stacked
• Stacked mode renders a vertical list of full-width options, each with a radio-style SVG indicator, option name, and optional description below the name
• Active/inactive states use custom SVGs (filled blue circle vs outlined grey circle)
• Options support a new description key for stacked mode; omitting it skips the description line
• layout is forwarded correctly through ToggleButtonInputComponent for form-integrated usage
• Demo showcase updated with a commission-type example showing all four variants (three with descriptions, one without)

Usage

<.odyssey_toggle_button
  layout={:stacked}
  options={[
    %{label: "Pre Tax Percentage Commission", value: :pre_tax, description: "Commission calculated before taxes are applied"},
    %{label: "After Tax Percentage Commission", value: :after_tax, description: "Commission calculated after taxes are applied"},
    %{label: "Flat Rate Commission", value: :flat_rate},
  ]}
  selected={@commission_type}
  on_change="change_commission_type"
/>