feat(map-editor): dropdown render for action/modal/toggle/separator

Renders the open dropdown for the active menu category with a
three-column item layout (indicator | label | hotkey). Toggle items
show their bound is_on() state with a [v]/[ ] indicator, modal
items append "...", separators draw as thin rules, disabled items
render in a muted colour. Submenu chevron is wired but submenus
themselves land in a later slice.

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

init.lua

@@ -612,6 +612,92 @@ local ui = (function()
         return out
     end
 
+    local function dropdown_width_for(items)
+        local w = DROPDOWN_MIN_W
+        for _, it in ipairs(items) do
+            if it.type ~= "separator" then
+                local label_w = engine.render.measure_text(it.label or "", 12)
+                local needed = DROPDOWN_INDICATOR_W + label_w + DROPDOWN_HOTKEY_W + 2 * DROPDOWN_PAD_X
+                if needed > w then w = needed end
+            end
+        end
+        return w
+    end
+
+    local function dropdown_layout(cat_layout)
+        local items = cat_layout.items
+        local w = dropdown_width_for(items)
+        local rows = {}
+        local y = cat_layout.y + cat_layout.h + DROPDOWN_PAD_Y
+        for i, it in ipairs(items) do
+            local row_h = (it.type == "separator") and 6 or DROPDOWN_ITEM_H
+            rows[i] = { item = it, x = cat_layout.x, y = y, w = w, h = row_h }
+            y = y + row_h
+        end
+        return {
+            x = cat_layout.x,
+            y = cat_layout.y + cat_layout.h + DROPDOWN_PAD_Y,
+            w = w,
+            h = y - (cat_layout.y + cat_layout.h + DROPDOWN_PAD_Y) + DROPDOWN_PAD_Y,
+            rows = rows,
+        }
+    end
+
+    local function item_is_disabled(item)
+        local d = item.disabled
+        if type(d) == "function" then return d() end
+        return d == true
+    end
+
+    local function draw_dropdown_item(row, hovered)
+        local it = row.item
+        if it.type == "separator" then
+            engine.render.draw_line(row.x + 6, row.y + 3,
+                                    row.x + row.w - 6, row.y + 3,
+                                    rgba(COL_TEXT_MUTED, 0x60))
+            return
+        end
+        local disabled = item_is_disabled(it)
+        if hovered and not disabled then
+            engine.render.draw_rect(row.x, row.y, row.w, row.h,
+                rgba(COL_ROW_HOVER, 0xFF))
+        end
+        local text_col = disabled and COL_TEXT_DISABLED or COL_TEXT
+        -- Left indicator gutter (toggle: [v] / [ ])
+        if it.type == "toggle" then
+            local on = it.is_on and it.is_on() or false
+            engine.render.draw_text(on and "[v]" or "[ ]",
+                row.x + 4, row.y + 5, 11,
+                rgba(on and COL_CHECK or COL_TEXT_MUTED, 0xFF))
+        end
+        -- Label
+        local label = it.label or ""
+        if it.type == "modal" then label = label .. "..." end
+        engine.render.draw_text(label,
+            row.x + DROPDOWN_INDICATOR_W + 2, row.y + 5, 12,
+            rgba(text_col, 0xFF))
+        -- Right column: hotkey or submenu chevron
+        if it.type == "submenu" then
+            engine.render.draw_text(">",
+                row.x + row.w - DROPDOWN_PAD_X - 6, row.y + 5, 12,
+                rgba(COL_TEXT_MUTED, 0xFF))
+        elseif it.hotkey then
+            engine.render.draw_text(it.hotkey,
+                row.x + row.w - DROPDOWN_HOTKEY_W, row.y + 5, 11,
+                rgba(COL_TEXT_MUTED, 0xFF))
+        end
+    end
+
+    local function draw_dropdown(cat_layout, mx, my)
+        local dd = dropdown_layout(cat_layout)
+        engine.render.draw_rect(dd.x, dd.y, dd.w, dd.h, rgba(COL_MODAL_BG, 0xFA))
+        engine.render.draw_rect_lines(dd.x, dd.y, dd.w, dd.h, rgba(COL_MODAL_BORDER, 0xFF))
+        for _, row in ipairs(dd.rows) do
+            local hovered = in_rect(mx, my, row.x, row.y, row.w, row.h)
+            draw_dropdown_item(row, hovered)
+        end
+    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))
@@ -884,6 +970,15 @@ local ui = (function()
     function M.draw()
         local mx, my = engine.input.get_mouse_pos()
         draw_menu_bar(mx, my)
+        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
+                    draw_dropdown(cat, mx, my)
+                    break
+                end
+            end
+        end
         draw_top_toolbar(mx, my)
         draw_mode_pill()
         draw_side_panel(mx, my)