feat: added a gallery quick action and fleshed out builtin macros

lib/bds/desktop/file_picker.ex

@@ -12,6 +12,17 @@ defmodule BDS.Desktop.FilePicker do
     end
   end
 
+  def choose_files(prompt, opts \\ []) when is_binary(prompt) do
+    if System.get_env("BDS_DESKTOP_AUTOMATION") == "1" do
+      :cancel
+    else
+      case :os.type() do
+        {:unix, :darwin} -> choose_files_macos(prompt, opts)
+        _other -> {:error, %{message: "File selection is only supported on macOS desktop"}}
+      end
+    end
+  end
+
   defp choose_file_macos(prompt) do
     script = "POSIX path of (choose file with prompt \"#{escape_applescript(prompt)}\")"
 
@@ -21,6 +32,50 @@ defmodule BDS.Desktop.FilePicker do
     end
   end
 
+  defp choose_files_macos(prompt, opts) do
+    multiple = Keyword.get(opts, :multiple, false)
+    image_only = Keyword.get(opts, :image_only, false)
+
+    script_parts = ["POSIX path of (choose file with prompt \"#{escape_applescript(prompt)}\""]
+
+    script_parts =
+      if image_only do
+        script_parts ++ [" of type {\"public.image\"}"]
+      else
+        script_parts
+      end
+
+    script_parts =
+      if multiple do
+        script_parts ++ [" with multiple selections allowed"]
+      else
+        script_parts
+      end
+
+    script = Enum.join(script_parts, "") <> ")"
+
+    case System.cmd("osascript", ["-e", script], stderr_to_stdout: true) do
+      {output, 0} -> parse_choose_files_result(String.trim(output), multiple)
+      {output, _status} -> normalize_picker_failure(output)
+    end
+  end
+
+  @doc false
+  def parse_choose_files_result(output, true = _multiple) do
+    paths =
+      output
+      |> String.split("\n")
+      |> Enum.map(&String.trim/1)
+      |> Enum.reject(&(&1 == ""))
+
+    {:ok, paths}
+  end
+
+  @doc false
+  def parse_choose_files_result(output, false = _multiple) do
+    {:ok, output}
+  end
+
   defp normalize_picker_failure(output) do
     message = String.trim(output)