fix: flatten nested case blocks with with chains (CSM-020)

Replace deeply nested case expressions with flat with chains in
import_definitions, publishing, and templates modules. Also replaced
Repo.update!() with Repo.update() in the publishing update_job handler.

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

test/bds/csm020_nested_case_test.exs

@@ -0,0 +1,91 @@
+defmodule BDS.CSM020NestedCaseTest do
+  use ExUnit.Case, async: false
+
+  alias BDS.ImportDefinitions
+  alias BDS.Templates
+
+  setup do
+    :ok = Ecto.Adapters.SQL.Sandbox.checkout(BDS.Repo)
+
+    temp_dir =
+      Path.join(System.tmp_dir!(), "bds-csm020-#{System.unique_integer([:positive])}")
+
+    File.mkdir_p!(temp_dir)
+    on_exit(fn -> File.rm_rf(temp_dir) end)
+
+    {:ok, project} =
+      BDS.Projects.create_project(%{name: "CSM-020 Test", data_path: temp_dir})
+
+    %{project: project, temp_dir: temp_dir}
+  end
+
+  describe "ImportDefinitions.delete_definition/1 uses with" do
+    test "returns {:ok, :deleted} on success", %{project: project} do
+      {:ok, definition} =
+        ImportDefinitions.create_definition(%{
+          project_id: project.id,
+          name: "test",
+          wxr_file_path: "/tmp/test.xml"
+        })
+
+      assert {:ok, :deleted} = ImportDefinitions.delete_definition(definition.id)
+    end
+
+    test "returns {:error, :not_found} for missing ID" do
+      assert {:error, :not_found} =
+               ImportDefinitions.delete_definition(Ecto.UUID.generate())
+    end
+
+    test "source code uses with instead of nested case" do
+      source = File.read!("lib/bds/import_definitions.ex")
+      [func_source] = Regex.scan(~r/def delete_definition.*?(?=\n  def |\n  @|\nend)/s, source)
+
+      refute func_source |> List.first() |> String.contains?("|> case do"),
+             "delete_definition should not pipe into case"
+    end
+  end
+
+  describe "Templates.update_template/2 uses with" do
+    test "returns {:error, :not_found} for missing ID" do
+      assert {:error, :not_found} = Templates.update_template(Ecto.UUID.generate(), %{})
+    end
+
+    test "updates title successfully", %{project: project} do
+      {:ok, template} =
+        Templates.create_template(%{
+          project_id: project.id,
+          title: "Original",
+          kind: :post,
+          content: "<p>test</p>"
+        })
+
+      assert {:ok, updated} =
+               Templates.update_template(template.id, %{title: "Updated"})
+
+      assert updated.title == "Updated"
+    end
+
+    test "source code uses with instead of deeply nested case" do
+      source = File.read!("lib/bds/templates.ex")
+
+      refute Regex.match?(
+               ~r/def update_template.*?case Repo\.get.*?case transaction_result/s,
+               source
+             ),
+             "update_template should not have nested case blocks"
+    end
+  end
+
+  describe "Publishing.handle_call :update_job uses with" do
+    test "source code uses with instead of case" do
+      source = File.read!("lib/bds/publishing.ex")
+      [func_source] = Regex.scan(~r/def handle_call\(\{:update_job.*?(?=\n  def |\n  @impl)/s, source)
+
+      assert func_source |> List.first() |> String.contains?("with"),
+             "update_job handler should use with"
+
+      refute func_source |> List.first() |> String.contains?("case Repo.get"),
+             "update_job handler should not use case Repo.get"
+    end
+  end
+end