feat(layout): implement responsive edge-to-edge card grid with density-aware column calculation

- Add dynamic column calculation based on container width and min card width
- Prevent tiny cards on narrow windows by respecting density-based minimums:
  - Default: 240px, Medium: 200px, Compact: 170px
- Fix edge-to-edge layout with proper CSS selector (.virtual-scroll-item.model-card)
- Add hamburger menu for mobile/small screens with proper translations
- Update all locale files with 'common.actions.menu' key

Fixes: Cards becoming too small/overlapping on narrow window widths (e.g., 1156px)
Changes: 15 files, +569/-114 lines

locales/zh-TW.json

@@ -15,7 +15,8 @@
             "settings": "設定",
             "help": "說明",
             "add": "新增",
-            "close": "關閉"
+            "close": "關閉",
+            "menu": "選單"
         },
         "status": {
             "loading": "載入中...",