Plugin still creates the removed "Reports" menu item; remove existing dead items #2136

Report

A customer clicked a menu entry and silently landed on "Mine eForms". While investigating, a second dead menu entry turned up on many installations: "Rapporter" → /plugins/items-planning-pn/reports.

Current behaviour

The items-planning plugin removed the reports route (commit 4a34171, 2023), but EformItemsPlanningPlugin.cs on stable still creates the "Reports" menu item. Clicking it matches no route, and the frontend's catch-all {path: '**', redirectTo: ''} sends the user to "Mine eForms" without any message. Over a hundred installations have this dead item.

Fix sketch

• Stop creating the "Reports" menu item in EformItemsPlanningPlugin.cs.
• At plugin start, remove existing menu items whose link is /plugins/items-planning-pn/reports (idempotent, logged).

Tests

Integration: plugin start on a DB that has the dead item → the item is removed; a second start is a no-op; no new item is created.

Related: frontend issue about unknown routes silently redirecting to "Mine eForms".