add live page editor sidebar with collapsible UI

Admins can now edit pages directly on the live shop by clicking the
pencil icon in the header. A sidebar slides in with block management
controls (add, remove, reorder, edit settings, save, reset, done).

Key features:
- PageEditorHook on_mount with handle_params/event/info hooks
- BlockEditor pure functions extracted from admin editor
- Shared BlockEditorComponents with event_prefix namespacing
- Collapsible sidebar: X closes it, header pencil reopens it
- Backdrop overlay dismisses sidebar on tap
- Conditional admin.css loading for logged-in users
- content_body block now portable (textarea setting + rich text fallback)

13 integration tests, 26 unit tests, 1370 total passing.

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

test/berrypod/pages/block_editor_test.exs

@@ -0,0 +1,187 @@
+defmodule Berrypod.Pages.BlockEditorTest do
+  use ExUnit.Case, async: true
+
+  alias Berrypod.Pages.BlockEditor
+
+  defp make_block(id, type, settings \\ %{}) do
+    %{"id" => id, "type" => type, "settings" => settings}
+  end
+
+  defp three_blocks do
+    [
+      make_block("a", "hero", %{"title" => "Welcome"}),
+      make_block("b", "featured_products"),
+      make_block("c", "image_text", %{"title" => "About us"})
+    ]
+  end
+
+  describe "move_up/2" do
+    test "moves a block up one position" do
+      {:ok, blocks, msg} = BlockEditor.move_up(three_blocks(), "b")
+
+      assert [%{"id" => "b"}, %{"id" => "a"}, %{"id" => "c"}] = blocks
+      assert msg =~ "moved to position"
+    end
+
+    test "returns :noop for the first block" do
+      assert :noop = BlockEditor.move_up(three_blocks(), "a")
+    end
+
+    test "returns :noop for unknown id" do
+      assert :noop = BlockEditor.move_up(three_blocks(), "zzz")
+    end
+  end
+
+  describe "move_down/2" do
+    test "moves a block down one position" do
+      {:ok, blocks, msg} = BlockEditor.move_down(three_blocks(), "b")
+
+      assert [%{"id" => "a"}, %{"id" => "c"}, %{"id" => "b"}] = blocks
+      assert msg =~ "moved to position"
+    end
+
+    test "returns :noop for the last block" do
+      assert :noop = BlockEditor.move_down(three_blocks(), "c")
+    end
+  end
+
+  describe "remove_block/2" do
+    test "removes the specified block" do
+      {:ok, blocks, msg} = BlockEditor.remove_block(three_blocks(), "b")
+
+      assert length(blocks) == 2
+      refute Enum.any?(blocks, &(&1["id"] == "b"))
+      assert msg =~ "removed"
+    end
+  end
+
+  describe "duplicate_block/2" do
+    test "inserts a copy after the original" do
+      {:ok, blocks, msg} = BlockEditor.duplicate_block(three_blocks(), "a")
+
+      assert length(blocks) == 4
+      assert Enum.at(blocks, 0)["id"] == "a"
+      # Copy is at index 1 with a new ID
+      copy = Enum.at(blocks, 1)
+      assert copy["type"] == "hero"
+      assert copy["id"] != "a"
+      assert copy["settings"] == %{"title" => "Welcome"}
+      assert msg =~ "duplicated"
+    end
+
+    test "returns :noop for unknown id" do
+      assert :noop = BlockEditor.duplicate_block(three_blocks(), "zzz")
+    end
+  end
+
+  describe "add_block/2" do
+    test "appends a new block of the given type" do
+      {:ok, blocks, msg} = BlockEditor.add_block(three_blocks(), "hero")
+
+      assert length(blocks) == 4
+      new = List.last(blocks)
+      assert new["type"] == "hero"
+      assert is_binary(new["id"])
+      assert msg =~ "added"
+    end
+
+    test "returns :noop for unknown block type" do
+      assert :noop = BlockEditor.add_block(three_blocks(), "nonexistent_block_type")
+    end
+  end
+
+  describe "update_settings/3" do
+    test "merges new settings into the block" do
+      {:ok, blocks} =
+        BlockEditor.update_settings(three_blocks(), "a", %{"title" => "New title"})
+
+      hero = Enum.find(blocks, &(&1["id"] == "a"))
+      assert hero["settings"]["title"] == "New title"
+    end
+
+    test "returns :noop for unknown block id" do
+      assert :noop = BlockEditor.update_settings(three_blocks(), "zzz", %{"title" => "Nope"})
+    end
+  end
+
+  describe "block_display_name/1" do
+    test "returns the block type name from registry" do
+      block = make_block("a", "hero")
+      assert BlockEditor.block_display_name(block) == "Hero banner"
+    end
+
+    test "returns the raw type for unknown types" do
+      block = make_block("a", "weird_thing")
+      assert BlockEditor.block_display_name(block) == "weird_thing"
+    end
+
+    test "handles nil" do
+      assert BlockEditor.block_display_name(nil) == "Block"
+    end
+  end
+
+  describe "has_settings?/1" do
+    test "returns true for blocks with settings schema" do
+      assert BlockEditor.has_settings?(make_block("a", "hero"))
+    end
+
+    test "returns false for blocks without settings" do
+      refute BlockEditor.has_settings?(make_block("a", "category_nav"))
+    end
+  end
+
+  describe "settings_with_defaults/1" do
+    test "fills in default values for missing settings" do
+      block = make_block("a", "hero", %{})
+      result = BlockEditor.settings_with_defaults(block)
+
+      # Hero has a title field with a default
+      assert is_binary(result["title"])
+    end
+
+    test "preserves existing settings" do
+      block = make_block("a", "hero", %{"title" => "Custom"})
+      result = BlockEditor.settings_with_defaults(block)
+
+      assert result["title"] == "Custom"
+    end
+  end
+
+  describe "coerce_settings/2" do
+    test "passes through string values" do
+      schema = [%{key: "title", type: :text, default: ""}]
+      result = BlockEditor.coerce_settings(%{"title" => "Hello"}, schema)
+      assert result["title"] == "Hello"
+    end
+
+    test "parses number fields" do
+      schema = [%{key: "columns", type: :number, default: 4}]
+      result = BlockEditor.coerce_settings(%{"columns" => "3"}, schema)
+      assert result["columns"] == 3
+    end
+
+    test "falls back to default for invalid numbers" do
+      schema = [%{key: "columns", type: :number, default: 4}]
+      result = BlockEditor.coerce_settings(%{"columns" => "abc"}, schema)
+      assert result["columns"] == 4
+    end
+  end
+
+  describe "parse_number/2" do
+    test "parses valid integer strings" do
+      assert BlockEditor.parse_number("42", 0) == 42
+    end
+
+    test "returns integer values as-is" do
+      assert BlockEditor.parse_number(7, 0) == 7
+    end
+
+    test "returns default for non-numeric strings" do
+      assert BlockEditor.parse_number("nope", 5) == 5
+    end
+
+    test "returns default for nil" do
+      assert BlockEditor.parse_number(nil, 10) == 10
+    end
+  end
+end