feat(module-grants): Proxmox, Handelsware und DKV mit Freigabestufe Verwalten

- Proxmox-Schreibwege und Handelsware-Einstellungen auf @ModuleManage umgestellt
- DKV-Fleet: ganze Klasse Verwalten-Stufe, Benutzen allein bleibt ohne Zugriff
- Metadaten-Test belegt umgestellte und bewusst Administratoren vorbehaltene Handler
- Webseiten (Proxmox, Handelsware, Widget) folgen canManage, DKV-Zugriffsseite erklärt die Stufe

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/web/src/messages/en.json

@@ -924,6 +924,7 @@
     "accessDenied": {
       "title": "No Access to This Module",
       "body": "You do not have access to this module. Please contact your administrator.",
+      "manageRequiredBody": "This module is only available to users who may manage it. Please contact your administrator.",
       "backToDashboard": "Back to Dashboard"
     }
   },
@@ -1011,7 +1012,7 @@
     },
     "settings": {
       "title": "Proxmox — Settings",
-      "accessDeniedText": "This page is only available to administrators.",
+      "accessDeniedText": "This page is available to administrators and to users who may manage this module.",
       "addServer": "Add server",
       "noServers": "No server configured yet.",
       "nameLabel": "Name",
@@ -1636,7 +1637,7 @@
     "notConfigured": {
       "admin": "Consultant number, client number and wage type have not been set yet. Without them no DATEV file can be created.",
       "adminAction": "Go to settings",
-      "user": "An administrator has to set the consultant number, client number and wage type first."
+      "user": "An administrator or someone who may manage this module has to set the consultant number, client number and wage type first."
     },
     "summary": {
       "title": "Check result",
@@ -1710,7 +1711,7 @@
     "notConfigured": {
       "admin": "The default revenue account and the starting counter account have not been set yet. Without them no accounts can be assigned.",
       "adminAction": "Go to settings",
-      "user": "An administrator has to set the default revenue account and the starting counter account first."
+      "user": "An administrator or someone who may manage this module has to set the default revenue account and the starting counter account first."
     },
     "import": {
       "dropPlaceholder": "Drag an Excel file here or click",