feat: add automated Printify mockup generation & POD sample content

Printify Integration:
- Add Printify API client module with full HTTP wrapper
- Add mockup generator with dynamic "cover" scaling algorithm
- Create Mix task (mix generate_mockups) for automated mockup generation
- Support --cleanup flag to delete products after downloading mockups
- Calculate optimal scale factor based on artwork/placeholder aspect ratios
- Handle landscape artwork on portrait print areas without white space

Sample Content (16 products across 5 POD categories):
- Art Prints: Mountain Sunrise, Ocean Waves, Wildflower Meadow, Geometric Abstract, Botanical Illustration
- Apparel: Forest Silhouette T-Shirt, Forest Light Hoodie
- Tote Bags: Wildflower Meadow, Sunset Gradient
- Homewares: Fern Leaf Mug, Ocean Waves Cushion, Night Sky Blanket
- Stationery: Autumn Leaves Notebook, Monstera Leaf Notebook
- Accessories: Monstera Leaf Phone Case, Blue Waves Laptop Sleeve

Preview Data Updates:
- Replace generic e-commerce products with POD-focused items
- Update categories to POD-relevant: Art Prints, Apparel, Homewares, Stationery, Accessories
- Update cart drawer items to match new product range
- Refresh testimonials with POD-appropriate reviews

Theme Content Updates:
- Update hero section for "Wildprint Studio" brand identity
- Rewrite about page narrative with humble, British, personal tone
- Update search hints to nature/POD relevant terms
- Add mockups directory to static paths

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lib/simpleshop_theme_web/live/theme_live/preview_pages.ex

@@ -142,10 +142,10 @@ defmodule SimpleshopThemeWeb.ThemeLive.PreviewPages do
           <!-- Newsletter -->
           <div>
             <h3 class="text-xl font-bold mb-2" style="font-family: var(--t-font-heading); color: var(--t-text-primary); font-weight: var(--t-heading-weight);">
-              Join the studio
+              Stay in touch
             </h3>
             <p class="mb-4 text-sm" style="color: var(--t-text-secondary);">
-              Get 10% off your first order and be the first to know about new prints.
+              Get 10% off your first order and be the first to know about new designs.
             </p>
             <form class="flex flex-wrap gap-2">
               <input
@@ -364,7 +364,7 @@ defmodule SimpleshopThemeWeb.ThemeLive.PreviewPages do
           </button>
         </div>
         <div class="p-6" style="color: var(--t-text-tertiary);">
-          <p class="text-sm">Try searching for "fern", "roses", or "botanical"</p>
+          <p class="text-sm">Try searching for "mountain", "forest", or "ocean"</p>
         </div>
       </div>
     </div>

lib/simpleshop_theme_web/live/theme_live/preview_pages/about.html.heex

@@ -15,7 +15,7 @@
         About the studio
       </h1>
       <p class="text-lg" style="color: var(--t-text-secondary);">
-        Nature-inspired art, made with care
+        Nature photography, printed with care
       </p>
     </div>
 
@@ -24,35 +24,39 @@
       <!-- About Image -->
       <div
         class="content-image about-image"
-        style="width: 100%; height: 300px; border-radius: var(--t-radius-image); margin-bottom: var(--space-lg); background-size: cover; background-position: center; background-image: url('https://picsum.photos/seed/studio/800/400');"
+        style="width: 100%; height: 300px; border-radius: var(--t-radius-image); margin-bottom: var(--space-lg); background-size: cover; background-position: center; background-image: url('/mockups/night-sky-blanket-3.jpg');"
       ></div>
 
       <!-- Content Text -->
       <div class="content-text" style="line-height: 1.7;">
         <p class="lead-text text-lg mb-4" style="color: var(--t-text-primary);">
-          Botanical Studio was born from a love of the natural world and a desire to bring its beauty indoors.
+          I'm Emma, a nature photographer based in the UK. What started as weekend walks with my camera has grown into something I never expected – a little shop where I can share my favourite captures with others.
         </p>
 
         <p class="mb-4" style="color: var(--t-text-secondary);">
-          Every illustration starts as a pencil sketch, inspired by the plants and flowers found in British woodlands, meadows, and gardens. These sketches are then refined and printed on museum-quality archival paper using pigment-based inks that will last a lifetime.
+          Every design in this shop comes from my own photography. Whether it's early morning mist over the hills, autumn leaves in the local woods, or the quiet beauty of wildflower meadows, I'm drawn to the peaceful moments that nature offers.
         </p>
 
         <p class="mb-4" style="color: var(--t-text-secondary);">
-          Based in the Yorkshire countryside, I work from a small garden studio surrounded by the very nature that inspires each piece. Every print is checked by hand before being carefully packaged and sent on its way.
+          I work with quality print partners to bring these images to life on products you can actually use and enjoy – from art prints for your walls to mugs for your morning tea.
         </p>
 
         <h2 class="mt-8 mb-3" style="font-family: var(--t-font-heading); font-weight: var(--t-heading-weight); font-size: var(--t-text-xl); color: var(--t-text-primary);">
-          Sustainability
+          Quality you can trust
         </h2>
         <p class="mb-4" style="color: var(--t-text-secondary);">
-          I believe beautiful art shouldn't cost the earth. All prints are produced on FSC-certified paper, shipped in plastic-free packaging, and printed locally to reduce transport emissions.
+          I've carefully chosen print partners who share my commitment to quality. Every product is made to order using premium materials and printing techniques that ensure vibrant colours and lasting quality.
         </p>
 
         <h2 class="mt-8 mb-3" style="font-family: var(--t-font-heading); font-weight: var(--t-heading-weight); font-size: var(--t-text-xl); color: var(--t-text-primary);">
-          The process
+          Printed sustainably
         </h2>
         <p class="mb-4" style="color: var(--t-text-secondary);">
-          Each botanical illustration takes between 20-40 hours to complete, from initial field sketches through to the final digital refinement. I work primarily in graphite and watercolour, which are then scanned and carefully colour-corrected to ensure the prints match the original artwork.
+          Because each item is printed on demand, there's no waste from unsold stock. My print partners use eco-friendly inks where possible, and products are shipped directly to you to minimise unnecessary handling.
+        </p>
+
+        <p class="mt-8" style="color: var(--t-text-secondary);">
+          Thank you for visiting. It means a lot that you're here.
         </p>
       </div>
     </div>

lib/simpleshop_theme_web/live/theme_live/preview_pages/home.html.heex

@@ -10,10 +10,10 @@
   <!-- Hero Section -->
   <section class="text-center" style="padding: var(--space-2xl) var(--space-lg); background-color: var(--t-surface-base);">
     <h1 class="text-3xl md:text-4xl mb-4" style="font-family: var(--t-font-heading); font-weight: var(--t-heading-weight); letter-spacing: var(--t-heading-tracking); color: var(--t-text-primary);">
-      Nature-inspired art prints
+      Original designs, printed on demand
     </h1>
     <p class="text-lg max-w-lg mx-auto mb-8" style="color: var(--t-text-secondary); line-height: 1.6;">
-      Original botanical illustrations, printed on premium archival paper. Each piece brings a little bit of the outside, inside.
+      From art prints to apparel – unique products created by independent artists and delivered straight to your door.
     </p>
     <button
       phx-click="change_preview_page"
@@ -45,7 +45,7 @@
   <!-- Featured Products -->
   <section style="padding: var(--space-xl) var(--space-lg); background-color: var(--t-surface-sunken);">
     <h2 class="text-2xl mb-6" style="font-family: var(--t-font-heading); font-weight: var(--t-heading-weight); letter-spacing: var(--t-heading-tracking); color: var(--t-text-primary);">
-      Featured prints
+      Featured products
     </h2>
 
     <div class={[
@@ -117,14 +117,14 @@
   <section class="grid grid-cols-1 md:grid-cols-2 gap-12 items-center" style="padding: var(--space-2xl) var(--space-lg); background-color: var(--t-surface-base);">
     <div
       class="h-72 rounded-lg bg-cover bg-center"
-      style="background-image: url('https://picsum.photos/seed/studio/600/400'); border-radius: var(--t-radius-image);"
+      style="background-image: url('/mockups/mountain-sunrise-print-3.jpg'); border-radius: var(--t-radius-image);"
     ></div>
     <div>
       <h2 class="text-2xl mb-4" style="font-family: var(--t-font-heading); font-weight: var(--t-heading-weight); letter-spacing: var(--t-heading-tracking); color: var(--t-text-primary);">
-        Made with care in Yorkshire
+        Made with passion, printed with care
       </h2>
       <p class="text-base mb-4" style="color: var(--t-text-secondary); line-height: 1.7;">
-        Every illustration starts as a pencil sketch, inspired by the plants and flowers found in British woodlands, meadows, and gardens. Printed on museum-quality archival paper using pigment-based inks that will last a lifetime.
+        Every design starts with an idea. We work with quality print partners to bring those ideas to life on premium products – from gallery-quality art prints to everyday essentials.
       </p>
       <a
         href="#"