consolidate all external links through external_link component

Add icon={false} option to external_link for links with their own
visual indicator. Migrate remaining manual target="_blank" links:
email settings adapter links, product show provider edit, card radio
links, social link cards/icons, page renderer tracking and video
fallback. Every external link in the codebase now goes through the
single component — one place to change rel, target, or sr-only text.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/berrypod_web/page_renderer.ex

@@ -16,7 +16,7 @@ defmodule BerrypodWeb.PageRenderer do
     statics: BerrypodWeb.static_paths()
 
   import BerrypodWeb.BlockEditorComponents
-  import BerrypodWeb.CoreComponents, only: [icon: 1]
+  import BerrypodWeb.CoreComponents, only: [icon: 1, external_link: 1]
 
   alias Berrypod.Cart
 
@@ -883,15 +883,12 @@ defmodule BerrypodWeb.PageRenderer do
               <% end %>
             </div>
             <%= if assigns[:order].tracking_url do %>
-              <a
+              <.external_link
                 href={assigns[:order].tracking_url}
-                target="_blank"
-                rel="noopener noreferrer"
                 class="order-detail-tracking-btn themed-button"
-                aria-label="Track parcel (opens in new tab)"
               >
                 Track parcel
-              </a>
+              </.external_link>
             <% end %>
           </div>
         </.shop_card>
@@ -1078,9 +1075,9 @@ defmodule BerrypodWeb.PageRenderer do
         </iframe>
       </div>
       <p :if={@provider == :unknown && @raw_url != ""} class="video-embed-fallback">
-        <a href={@raw_url} target="_blank" rel="noopener noreferrer">
+        <.external_link href={@raw_url}>
           {if @caption != "", do: @caption, else: "Watch video"}
-        </a>
+        </.external_link>
       </p>
       <p :if={@caption != "" && @provider != :unknown} class="video-embed-caption">{@caption}</p>
     </div>