feat(connections): enable persistent column visibility and ordering #5235 (#5249)

* feat(connections): enable persistent column visibility and ordering

fix(connections): smooth column manager access in table view

fix(connections): integrate column manager into column menu

- Move the Connections column manager trigger into the DataGrid column menu, reusing existing i18n strings
- Clean up the page toolbar by removing the standalone button and lifting dialog state to the parent page

fix(connections): unify column order handling and resolve lint warnings

fix(connections): unify column order handling and enforce 0 ESLint warnings

- extract reconcileColumnOrder helper and reuse it across:
  - initial normalization (useEffect)
  - manager drag order handler (handleManagerOrderChange)
- derive columnOptions directly from the computed, sorted columns to keep a single source of truth and prevent dialog/grid drift
- connections.tsx: remove direct setState in useEffect; gate dialog open with `isTableLayout && isColumnManagerOpen`; clean up unused imports
- connection-column-manager.tsx: replace deprecated `primaryTypographyProps` with `slotProps`
- run full lint; project now has 0 warnings on main configuration

* feat(connection-table): safeguard column visibility

---------

Co-authored-by: Slinetrac <realakayuki@gmail.com>

src/locales/jp/connections.json

@@ -23,6 +23,10 @@
     },
     "actions": {
       "closeConnection": "接続を閉じる"
+    },
+    "columnManager": {
+      "title": "列",
+      "dragHandle": "Drag handle"
     }
   }
 }