feat: add Settings and Media contexts with theme settings schema

- Create settings table for site-wide key-value configuration
- Create images table for BLOB storage of logo/header images
- Add Setting schema with JSON/string/integer/boolean support
- Add ThemeSettings embedded schema with all theme options
- Add Settings context with get/put/update operations
- Add Media context for image uploads and retrieval
- Add Image schema with SVG detection and storage
- Add 9 curated theme presets (gallery, studio, boutique, etc.)
- Add comprehensive tests for Settings and Media contexts
- Add seeds with default Studio preset
- All tests passing (29 tests, 0 failures)

lib/simpleshop_theme/settings/setting.ex

@@ -0,0 +1,24 @@
+defmodule SimpleshopTheme.Settings.Setting do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  @primary_key {:id, :binary_id, autogenerate: true}
+  @foreign_key_type :binary_id
+
+  schema "settings" do
+    field :key, :string
+    field :value, :string
+    field :value_type, :string, default: "string"
+
+    timestamps(type: :utc_datetime)
+  end
+
+  @doc false
+  def changeset(setting, attrs) do
+    setting
+    |> cast(attrs, [:key, :value, :value_type])
+    |> validate_required([:key, :value, :value_type])
+    |> validate_inclusion(:value_type, ~w(string json integer boolean))
+    |> unique_constraint(:key)
+  end
+end

lib/simpleshop_theme/settings/theme_settings.ex

@@ -0,0 +1,101 @@
+defmodule SimpleshopTheme.Settings.ThemeSettings do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  @derive Jason.Encoder
+  @primary_key false
+  embedded_schema do
+    # Core theme tokens
+    field :mood, :string, default: "neutral"
+    field :typography, :string, default: "clean"
+    field :shape, :string, default: "soft"
+    field :density, :string, default: "balanced"
+    field :grid_columns, :string, default: "4"
+    field :header_layout, :string, default: "standard"
+    field :accent_color, :string, default: "#f97316"
+
+    # Branding
+    field :logo_mode, :string, default: "text-only"
+    field :logo_image_id, :binary_id
+    field :header_image_id, :binary_id
+    field :logo_size, :integer, default: 36
+    field :logo_recolor, :boolean, default: false
+    field :logo_color, :string, default: "#171717"
+    field :header_zoom, :integer, default: 100
+    field :header_position_x, :integer, default: 50
+    field :header_position_y, :integer, default: 50
+
+    # Advanced customization
+    field :secondary_accent_color, :string, default: "#ea580c"
+    field :sale_color, :string, default: "#dc2626"
+    field :font_size, :string, default: "medium"
+    field :heading_weight, :string, default: "bold"
+    field :layout_width, :string, default: "wide"
+    field :button_style, :string, default: "filled"
+    field :card_shadow, :string, default: "none"
+    field :product_text_align, :string, default: "left"
+    field :image_aspect_ratio, :string, default: "square"
+
+    # Feature toggles
+    field :announcement_bar, :boolean, default: true
+    field :sticky_header, :boolean, default: false
+    field :hover_image, :boolean, default: true
+    field :quick_add, :boolean, default: true
+    field :show_prices, :boolean, default: true
+    field :pdp_trust_badges, :boolean, default: true
+    field :pdp_reviews, :boolean, default: true
+    field :pdp_related_products, :boolean, default: true
+  end
+
+  @doc false
+  def changeset(settings, attrs) do
+    settings
+    |> cast(attrs, [
+      :mood,
+      :typography,
+      :shape,
+      :density,
+      :grid_columns,
+      :header_layout,
+      :accent_color,
+      :logo_mode,
+      :logo_image_id,
+      :header_image_id,
+      :logo_size,
+      :logo_recolor,
+      :logo_color,
+      :header_zoom,
+      :header_position_x,
+      :header_position_y,
+      :secondary_accent_color,
+      :sale_color,
+      :font_size,
+      :heading_weight,
+      :layout_width,
+      :button_style,
+      :card_shadow,
+      :product_text_align,
+      :image_aspect_ratio,
+      :announcement_bar,
+      :sticky_header,
+      :hover_image,
+      :quick_add,
+      :show_prices,
+      :pdp_trust_badges,
+      :pdp_reviews,
+      :pdp_related_products
+    ])
+    |> validate_required([:mood, :typography, :shape, :density])
+    |> validate_inclusion(:mood, ~w(neutral warm cool dark))
+    |> validate_inclusion(:typography, ~w(clean editorial modern classic friendly minimal impulse))
+    |> validate_inclusion(:shape, ~w(sharp soft round pill))
+    |> validate_inclusion(:density, ~w(spacious balanced compact))
+    |> validate_inclusion(:grid_columns, ~w(2 3 4))
+    |> validate_inclusion(:header_layout, ~w(standard centered minimal))
+    |> validate_inclusion(:logo_mode, ~w(text-only logo-text logo-only header-image logo-header))
+    |> validate_number(:logo_size, greater_than_or_equal_to: 24, less_than_or_equal_to: 120)
+    |> validate_number(:header_zoom, greater_than_or_equal_to: 100, less_than_or_equal_to: 200)
+    |> validate_number(:header_position_x, greater_than_or_equal_to: 0, less_than_or_equal_to: 100)
+    |> validate_number(:header_position_y, greater_than_or_equal_to: 0, less_than_or_equal_to: 100)
+  end
+end