feat(map-editor): Esc cascades modal -> menu -> quit

Esc no longer immediately exits the editor; it first dismisses any
open modal, then any open dropdown menu, and only falls through to
engine.exit() when no overlay is up.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

init.lua

@@ -330,6 +330,7 @@ local actions = (function()
     function M.set_mode(m)         state.set_mode(m) end
     function M.open_cheatsheet()  state.open_modal("cheatsheet") end
     function M.close_modal()      state.close_modal() end
+    function M.close_menu()       state.close_menu() end
 
     -- 0.2.0c actions
     function M.toggle_flip()       state.toggle_flip() end
@@ -1004,11 +1005,17 @@ function update(ctx, dt)
         end
     end
 
-    -- Quit
+    -- Esc precedence: modal → dropdown → quit
     if input.was_action_pressed("quit") then
+        if state.is_modal_open() then
+            actions.close_modal()
+        elseif state.get_menu_open() then
+            actions.close_menu()
+        else
             engine.exit()
             return
         end
+    end
 
     -- Update mouse-cell tracking for status chip
     local mx, my = engine.input.get_mouse_pos()