style: consistent back button and some translations

lib/mv_web/components/core_components.ex

@@ -111,7 +111,7 @@ defmodule MvWeb.CoreComponents do
       <.button variant="ghost" size="sm">Edit</.button>
       <.button disabled={true}>Disabled</.button>
   """
-  attr :rest, :global, include: ~w(href navigate patch method data-testid)
+  attr :rest, :global, include: ~w(href navigate patch method data-testid form)
 
   attr :variant, :string,
     values: ~w(primary secondary neutral ghost outline danger link icon),
@@ -633,17 +633,24 @@ defmodule MvWeb.CoreComponents do
 
   @doc """
   Renders a header with title.
+
+  Use the `:leading` slot for the Back button (left side, consistent with data fields).
+  Use the `:actions` slot for primary actions (e.g. Save) on the right.
   """
   attr :class, :string, default: nil
 
+  slot :leading, doc: "Content on the left (e.g. Back button)"
   slot :inner_block, required: true
   slot :subtitle
   slot :actions
 
   def header(assigns) do
     ~H"""
-    <header class={[@actions != [] && "flex items-center justify-between gap-6", "pb-4", @class]}>
-      <div>
+    <header class={["flex items-center gap-6 pb-4", @class]}>
+      <div :if={@leading != []} class="shrink-0">
+        {render_slot(@leading)}
+      </div>
+      <div class="min-w-0 flex-1">
         <h1 class="text-xl font-semibold leading-8">
           {render_slot(@inner_block)}
         </h1>
@@ -651,7 +658,9 @@ defmodule MvWeb.CoreComponents do
           {render_slot(@subtitle)}
         </p>
       </div>
-      <div class="flex gap-4 justify-end">{render_slot(@actions)}</div>
+      <div :if={@actions != []} class="shrink-0 flex gap-4 justify-end">
+        {render_slot(@actions)}
+      </div>
     </header>
     """
   end