feat(map-editor): dropdown click dispatch

Routes clicks on dropdown items to their per-type handler:
action.fire, open_modal for modal items, toggle.fire for toggles.
Disabled items absorb without closing; separators are inert.
Clicks outside the open dropdown close the menu and fall through to
canvas handling.

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

init.lua

@@ -698,6 +698,23 @@ local ui = (function()
         end
     end
 
+    local function fire_item(it)
+        if item_is_disabled(it) then return false end  -- absorbed, no close
+        if it.type == "action" then
+            if it.fire then it.fire() end
+            return true                                 -- close menu
+        elseif it.type == "modal" then
+            if it.modal_id then state.open_modal(it.modal_id) end
+            return true
+        elseif it.type == "toggle" then
+            if it.fire then it.fire() end
+            return true
+        elseif it.type == "submenu" then
+            return false                                -- handled separately
+        end
+        return false
+    end
+
     local function draw_menu_bar(mx, my)
         local screen_w = engine.window.size()
         engine.render.draw_rect(0, 0, screen_w, MENU_BAR_H, rgba(COL_TOOLBAR_BG, 0xFF))
@@ -1116,10 +1133,33 @@ local ui = (function()
             end
         end
 
-        -- Click anywhere outside the menu bar closes any open dropdown
+        -- Dropdown items
-        if state.get_menu_open() and my >= MENU_BAR_H then
+        local open_name = state.get_menu_open()
+        if open_name then
+            for _, cat in ipairs(menu_bar_categories_layout()) do
+                if cat.name == open_name then
+                    local dd = dropdown_layout(cat)
+                    if in_rect(mx, my, dd.x, dd.y, dd.w, dd.h) then
+                        if button == "left" then
+                            for _, row in ipairs(dd.rows) do
+                                if in_rect(mx, my, row.x, row.y, row.w, row.h) then
+                                    if row.item.type ~= "separator" then
+                                        if fire_item(row.item) then
+                                            state.close_menu()
+                                        end
+                                    end
+                                    return true
+                                end
+                            end
+                        end
+                        return true   -- empty area inside dropdown, absorbed
+                    end
+                    break
+                end
+            end
+            -- Click outside the dropdown closes it (no return — fall through so
+            -- the click can also hit other UI like canvas).
             state.close_menu()
-            -- Fall through (do not return) so the click can hit something else.
         end
 
         -- Top toolbar buttons