add canonical URLs, robots.txt, and sitemap.xml

Canonical: all shop pages now assign og_url (reusing the existing og:url
assign), which the layout renders as <link rel="canonical">. Collection
pages strip the sort param so ?sort=price_asc doesn't create a duplicate
canonical.

robots.txt: dynamic controller disallows /admin/, /api/, /users/,
/webhooks/, /checkout/. Removed robots.txt from static_paths so it
goes through the router instead of Plug.Static.

sitemap.xml: auto-generated from all visible products + categories +
static pages, served as application/xml. 8 tests.

Also updates PROGRESS.md: marks tasks 55, 58, 59, 61, 62 as done.

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

lib/berrypod_web/live/shop/collection.ex

@@ -32,6 +32,7 @@ defmodule BerrypodWeb.Shop.Collection do
          socket
          |> assign(:page_title, title)
          |> assign(:page_description, collection_description(title))
+         |> assign(:og_url, BerrypodWeb.Endpoint.url() <> "/collections/#{slug}")
          |> assign(:collection_title, title)
          |> assign(:current_category, category)
          |> assign(:current_sort, sort)

lib/berrypod_web/live/shop/contact.ex

@@ -6,7 +6,11 @@ defmodule BerrypodWeb.Shop.Contact do
     {:ok,
      socket
      |> assign(:page_title, "Contact")
-     |> assign(:page_description, "Get in touch with us for any questions or help with your order.")}
+     |> assign(
+       :page_description,
+       "Get in touch with us for any questions or help with your order."
+     )
+     |> assign(:og_url, BerrypodWeb.Endpoint.url() <> "/contact")}
   end
 
   @impl true

lib/berrypod_web/live/shop/content.ex

@@ -25,6 +25,7 @@ defmodule BerrypodWeb.Shop.Content do
     %{
       page_title: "About",
       page_description: "Your story goes here – this is sample content for the demo shop",
+      og_url: BerrypodWeb.Endpoint.url() <> "/about",
       active_page: "about",
       hero_title: "About the studio",
       hero_description: "Your story goes here – this is sample content for the demo shop",
@@ -39,6 +40,7 @@ defmodule BerrypodWeb.Shop.Content do
     %{
       page_title: "Delivery & returns",
       page_description: "Everything you need to know about shipping and returns.",
+      og_url: BerrypodWeb.Endpoint.url() <> "/delivery",
       active_page: "delivery",
       hero_title: "Delivery & returns",
       hero_description: "Everything you need to know about shipping and returns",
@@ -50,6 +52,7 @@ defmodule BerrypodWeb.Shop.Content do
     %{
       page_title: "Privacy policy",
       page_description: "How we handle your personal information.",
+      og_url: BerrypodWeb.Endpoint.url() <> "/privacy",
       active_page: "privacy",
       hero_title: "Privacy policy",
       hero_description: "How we handle your personal information",
@@ -61,6 +64,7 @@ defmodule BerrypodWeb.Shop.Content do
     %{
       page_title: "Terms of service",
       page_description: "The terms and conditions governing purchases from our shop.",
+      og_url: BerrypodWeb.Endpoint.url() <> "/terms",
       active_page: "terms",
       hero_title: "Terms of service",
       hero_description: "The legal bits",

lib/berrypod_web/live/shop/home.ex

@@ -10,6 +10,7 @@ defmodule BerrypodWeb.Shop.Home do
     socket =
       socket
       |> assign(:page_title, "Home")
+      |> assign(:og_url, BerrypodWeb.Endpoint.url() <> "/")
       |> assign(:products, products)
 
     {:ok, socket}