feat: add bulk email copy for selected members (#230)

Copy selected members' emails to clipboard in 'First Last <email>' format

lib/mv_web/live/member_live/index.html.heex

@@ -2,6 +2,16 @@
   <.header>
     {gettext("Members")}
     <:actions>
+      <.button
+        :if={Enum.any?(@members, &(&1.id in @selected_members))}
+        id="copy-emails-btn"
+        phx-hook="CopyToClipboard"
+        phx-click="copy_emails"
+        aria-label={gettext("Copy email addresses of selected members")}
+      >
+        <.icon name="hero-clipboard-document" />
+        {gettext("Copy emails")} ({Enum.count(@members, &(&1.id in @selected_members))})
+      </.button>
       <.button variant="primary" navigate={~p"/members/new"}>
         <.icon name="hero-plus" /> {gettext("New Member")}
       </.button>