Sidekick: Add Gift Message Option at Checkout

Help me add a gift message option to my Shopify checkout:

Store name: [YOUR STORE NAME]
Gift-eligible products: [ALL PRODUCTS / SPECIFIC COLLECTIONS]
Gift wrapping available: [YES / NO]
Gift wrapping fee: [AMOUNT OR FREE]

Set up the gift message feature as follows:


  
    Gift checkbox - Add a “This is a gift” checkbox in the checkout, placed after the shipping address section. When checked, expand a gift options panel below.
  
  
    Gift message field - Display a text area labeled “Gift message (optional)” with a character limit of [200 / 300 / 500] characters. Show a character counter so customers know how much space they have remaining.
  
  
    Gift wrapping option - If gift wrapping is available, add a checkbox for “Add gift wrapping” with the fee displayed (or “Free” if complimentary). Show a small preview image of your gift wrapping style.
  
  
    Packing slip behavior - When a gift message is included, automatically generate a packing slip that shows the gift message but hides all pricing information. Include the sender name and recipient name on the packing slip.
  
  
    Order management - Ensure the gift message and gift wrapping selection appear in the Shopify order details page. Tag orders with “gift-order” automatically so your fulfillment team can easily identify them.
  
  
    Email notifications - Do not send the order confirmation email to the shipping address if it differs from the billing address, to avoid spoiling the gift surprise. Send it only to the billing email.
  
  
    Cart page preview - Also add the gift message option on the cart page so customers can add it before reaching checkout. Sync the selection between cart and checkout.
  


Provide the implementation steps using Shopify checkout extensibility or a recommended app.