add favicon and site icon generation from uploaded images

Upload a source image (PNG, JPEG, or SVG) and get a complete favicon
setup: PNG variants at 32, 180, 192, 512px served from DB via
FaviconController with ETag caching, SVG favicon for vector sources,
dynamic site.webmanifest, and theme-color meta tag. Theme editor gains
a site icon section with "use logo as icon" toggle, dedicated icon
upload, short name, and background colour picker.

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

test/berrypod/media_test.exs

@@ -46,6 +46,12 @@ defmodule Berrypod.MediaTest do
       assert "is invalid" in errors_on(changeset).image_type
     end
 
+    test "accepts icon image type" do
+      attrs = Map.put(@valid_attrs, :image_type, "icon")
+      assert {:ok, image} = Media.upload_image(attrs)
+      assert image.image_type == "icon"
+    end
+
     test "validates file size" do
       attrs = Map.put(@valid_attrs, :file_size, 10_000_000)
       assert {:error, changeset} = Media.upload_image(attrs)
@@ -110,4 +116,77 @@ defmodule Berrypod.MediaTest do
       assert Media.list_images_by_type("product") == []
     end
   end
+
+  describe "get_icon/0" do
+    test "returns the most recent icon image" do
+      attrs = Map.put(@valid_attrs, :image_type, "icon")
+      {:ok, icon} = Media.upload_image(attrs)
+
+      result = Media.get_icon()
+      assert result.id == icon.id
+      assert result.image_type == "icon"
+    end
+
+    test "returns nil when no icons exist" do
+      assert Media.get_icon() == nil
+    end
+  end
+
+  describe "favicon variants" do
+    defp create_source_image do
+      {:ok, image} = Media.upload_image(@valid_attrs)
+      image
+    end
+
+    test "stores and retrieves favicon variants" do
+      image = create_source_image()
+
+      {:ok, variants} =
+        Media.store_favicon_variants(%{
+          source_image_id: image.id,
+          png_32: <<1, 2, 3>>,
+          png_180: <<4, 5, 6>>,
+          png_192: <<7, 8, 9>>,
+          png_512: <<10, 11, 12>>
+        })
+
+      assert variants.png_32 == <<1, 2, 3>>
+
+      fetched = Media.get_favicon_variants()
+      assert fetched.id == variants.id
+      assert fetched.png_32 == <<1, 2, 3>>
+      assert fetched.png_512 == <<10, 11, 12>>
+    end
+
+    test "replaces existing variants on store" do
+      image = create_source_image()
+
+      {:ok, first} =
+        Media.store_favicon_variants(%{
+          source_image_id: image.id,
+          png_32: <<1>>,
+          png_180: <<2>>,
+          png_192: <<3>>,
+          png_512: <<4>>
+        })
+
+      {:ok, second} =
+        Media.store_favicon_variants(%{
+          source_image_id: image.id,
+          png_32: <<5>>,
+          png_180: <<6>>,
+          png_192: <<7>>,
+          png_512: <<8>>
+        })
+
+      assert second.id != first.id
+      fetched = Media.get_favicon_variants()
+      assert fetched.id == second.id
+      assert fetched.png_32 == <<5>>
+    end
+
+    test "returns nil when no variants exist" do
+      assert Media.get_favicon_variants() == nil
+    end
+  end
 end

test/berrypod/workers/favicon_generator_worker_test.exs

@@ -0,0 +1,88 @@
+defmodule Berrypod.Workers.FaviconGeneratorWorkerTest do
+  use Berrypod.DataCase, async: false
+
+  import Berrypod.ImageFixtures
+
+  alias Berrypod.Media
+  alias Berrypod.Workers.FaviconGeneratorWorker
+
+  describe "perform/1" do
+    test "generates PNG variants from a raster image" do
+      image = image_fixture(%{image_type: "icon"})
+
+      assert :ok =
+               FaviconGeneratorWorker.perform(%Oban.Job{
+                 args: %{"source_image_id" => image.id}
+               })
+
+      variants = Media.get_favicon_variants()
+      assert variants != nil
+      assert variants.source_image_id == image.id
+      assert is_binary(variants.png_32)
+      assert is_binary(variants.png_180)
+      assert is_binary(variants.png_192)
+      assert is_binary(variants.png_512)
+      assert variants.svg == nil
+      assert variants.generated_at != nil
+    end
+
+    test "generates correct PNG sizes" do
+      image = image_fixture(%{image_type: "icon"})
+
+      :ok =
+        FaviconGeneratorWorker.perform(%Oban.Job{
+          args: %{"source_image_id" => image.id}
+        })
+
+      variants = Media.get_favicon_variants()
+
+      # Verify PNG data starts with PNG magic bytes
+      for field <- [:png_32, :png_180, :png_192, :png_512] do
+        data = Map.get(variants, field)
+        assert <<137, 80, 78, 71, _rest::binary>> = data, "#{field} should be valid PNG"
+      end
+    end
+
+    test "stores SVG as-is for SVG source" do
+      image = svg_fixture()
+
+      :ok =
+        FaviconGeneratorWorker.perform(%Oban.Job{
+          args: %{"source_image_id" => image.id}
+        })
+
+      variants = Media.get_favicon_variants()
+      assert variants != nil
+      assert is_binary(variants.svg)
+      assert variants.svg == image.svg_content
+    end
+
+    test "replaces existing variants on regeneration" do
+      image = image_fixture(%{image_type: "icon"})
+
+      :ok =
+        FaviconGeneratorWorker.perform(%Oban.Job{
+          args: %{"source_image_id" => image.id}
+        })
+
+      first_variants = Media.get_favicon_variants()
+      first_id = first_variants.id
+
+      # Generate again
+      :ok =
+        FaviconGeneratorWorker.perform(%Oban.Job{
+          args: %{"source_image_id" => image.id}
+        })
+
+      second_variants = Media.get_favicon_variants()
+      assert second_variants.id != first_id
+    end
+
+    test "cancels when image not found" do
+      assert {:cancel, :image_not_found} =
+               FaviconGeneratorWorker.perform(%Oban.Job{
+                 args: %{"source_image_id" => Ecto.UUID.generate()}
+               })
+    end
+  end
+end