feat: add dark mode support, accordion UI, and current combination display

- Update Theme Studio sidebar to use DaisyUI theme-aware classes for dark mode
- Convert Customise accordion to native details/summary elements for proper interaction
- Add "Current combination" card showing active theme settings
- Add SVG recolorer for logo color customization
- Add image controller for serving uploaded images
- Implement header background image controls (zoom, position)
- Add toggle_customise event handler to preserve accordion state across re-renders

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

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

test/simpleshop_theme_web/controllers/image_controller_test.exs

@@ -0,0 +1,124 @@
+defmodule SimpleshopThemeWeb.ImageControllerTest do
+  use SimpleshopThemeWeb.ConnCase
+
+  alias SimpleshopTheme.Media
+
+  @png_binary <<137, 80, 78, 71, 13, 10, 26, 10>>
+  @svg_content ~s(<svg xmlns="http://www.w3.org/2000/svg"><circle fill="#000000" r="10"/></svg>)
+
+  describe "show/2" do
+    test "returns 404 for non-existent image", %{conn: conn} do
+      conn = get(conn, ~p"/images/#{Ecto.UUID.generate()}")
+      assert response(conn, 404) =~ "Image not found"
+    end
+
+    test "serves image with proper content type and caching headers", %{conn: conn} do
+      {:ok, image} =
+        Media.upload_image(%{
+          image_type: "logo",
+          filename: "test.png",
+          content_type: "image/png",
+          file_size: byte_size(@png_binary),
+          data: @png_binary
+        })
+
+      conn = get(conn, ~p"/images/#{image.id}")
+
+      assert response(conn, 200) == @png_binary
+      assert get_resp_header(conn, "content-type") == ["image/png; charset=utf-8"]
+      assert get_resp_header(conn, "cache-control") == ["public, max-age=31536000, immutable"]
+      assert get_resp_header(conn, "etag") == [~s("#{image.id}")]
+    end
+  end
+
+  describe "thumbnail/2" do
+    test "returns 404 for non-existent image", %{conn: conn} do
+      conn = get(conn, ~p"/images/#{Ecto.UUID.generate()}/thumbnail")
+      assert response(conn, 404) =~ "Image not found"
+    end
+
+    test "falls back to full image when no thumbnail available", %{conn: conn} do
+      {:ok, image} =
+        Media.upload_image(%{
+          image_type: "logo",
+          filename: "test.png",
+          content_type: "image/png",
+          file_size: byte_size(@png_binary),
+          data: @png_binary
+        })
+
+      conn = get(conn, ~p"/images/#{image.id}/thumbnail")
+
+      assert response(conn, 200) == @png_binary
+      assert get_resp_header(conn, "content-type") == ["image/png; charset=utf-8"]
+    end
+  end
+
+  describe "recolored_svg/2" do
+    test "returns 404 for non-existent image", %{conn: conn} do
+      conn = get(conn, ~p"/images/#{Ecto.UUID.generate()}/recolored/ff6600")
+      assert response(conn, 404) =~ "Image not found"
+    end
+
+    test "returns 400 for non-SVG image", %{conn: conn} do
+      {:ok, image} =
+        Media.upload_image(%{
+          image_type: "logo",
+          filename: "test.png",
+          content_type: "image/png",
+          file_size: byte_size(@png_binary),
+          data: @png_binary
+        })
+
+      conn = get(conn, ~p"/images/#{image.id}/recolored/ff6600")
+      assert response(conn, 400) =~ "not an SVG"
+    end
+
+    test "returns 400 for invalid color", %{conn: conn} do
+      {:ok, image} =
+        Media.upload_image(%{
+          image_type: "logo",
+          filename: "test.svg",
+          content_type: "image/svg+xml",
+          file_size: byte_size(@svg_content),
+          data: @svg_content
+        })
+
+      conn = get(conn, ~p"/images/#{image.id}/recolored/invalid")
+      assert response(conn, 400) =~ "Invalid color"
+    end
+
+    test "recolors SVG with valid hex color", %{conn: conn} do
+      {:ok, image} =
+        Media.upload_image(%{
+          image_type: "logo",
+          filename: "test.svg",
+          content_type: "image/svg+xml",
+          file_size: byte_size(@svg_content),
+          data: @svg_content
+        })
+
+      conn = get(conn, ~p"/images/#{image.id}/recolored/ff6600")
+
+      assert response(conn, 200) =~ ~s(fill="#ff6600")
+      assert get_resp_header(conn, "content-type") == ["image/svg+xml; charset=utf-8"]
+      assert get_resp_header(conn, "cache-control") == ["public, max-age=3600"]
+    end
+
+    test "handles color with leading hash", %{conn: conn} do
+      {:ok, image} =
+        Media.upload_image(%{
+          image_type: "logo",
+          filename: "test.svg",
+          content_type: "image/svg+xml",
+          file_size: byte_size(@svg_content),
+          data: @svg_content
+        })
+
+      # URL encodes # as %23
+      conn = get(conn, "/images/#{image.id}/recolored/%23ff6600")
+
+      assert response(conn, 200) =~ ~s(fill="#ff6600")
+    end
+  end
+end