feat(260929-dzu): Einstellungen > Eigene Module fuer jeden Benutzer, Verwaltung nur gemeinsam

- gemeinsame Oberflaeche (CustomModuleManager, Formular, Loeschdialog) fuer Verwaltung und Einstellungen
- Einstellungen: persoenliche Eintraege, Verwaltung sendet shared: true und zeigt nur gemeinsame
- Navigation, Texte de/en, Komponententests

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

apps/web/src/messages/en.json

@@ -165,6 +165,7 @@
     "categoryGeneral": "General",
     "categoryAccount": "Account",
     "categoryDesktopApp": "Desktop App",
+    "categoryCustomModules": "Custom modules",
     "categorySmtp": "SMTP",
     "account": {
       "title": "Account",
@@ -228,6 +229,13 @@
       "testFailed": "Connection failed",
       "bugReportRecipient": "Bug reports to",
       "bugReportRecipientHelp": "Optional – mailbox that receives the reports users send via the \"Report a problem\" button, including the screenshot. Leave empty if the button should not send e-mails."
+    },
+    "customModules": {
+      "title": "Custom modules",
+      "description": "Add websites you use often as your own entries in your sidebar. Only you can see these entries. A click shows the page right inside Tessera.",
+      "create": "Add custom module",
+      "noModules": "No custom modules yet",
+      "noModulesBody": "Add your first module to show a website in your sidebar."
     }
   },
   "widgets": {
@@ -672,26 +680,10 @@
     },
     "customModules": {
       "title": "Custom modules",
-      "description": "Add other websites as entries in the sidebar. All users see these entries under the chosen category, and a click shows the page right inside Tessera.",
-      "create": "Add custom module",
-      "edit": "Edit custom module",
-      "name": "Name",
-      "url": "Address",
-      "urlHint": "The address must start with https://.",
-      "category": "Category",
-      "actions": "Actions",
-      "noModules": "No custom modules yet",
-      "noModulesBody": "Add your first module to show a website in the sidebar.",
-      "nameRequired": "Please enter a name.",
-      "urlNotHttps": "Please enter an address that starts with https://.",
-      "urlCredentials": "The address must not contain a user name or a password.",
-      "saveError": "The module could not be saved. Please try again.",
-      "deleteError": "The module could not be deleted. Please try again.",
-      "loadError": "The custom modules could not be loaded.",
-      "deleteConfirm": {
-        "title": "Delete custom module",
-        "body": "Do you really want to delete “{name}”? The entry disappears from the sidebar for all users."
-      }
+      "description": "Add other websites as entries in the sidebar. All users see these shared entries under the chosen category, and a click shows the page right inside Tessera. Personal entries only you can see are added under “Settings → Custom modules”.",
+      "create": "Add shared entry",
+      "noModules": "No shared entries yet",
+      "noModulesBody": "Add your first shared entry to show a website in the sidebar for all users."
     }
   },
   "adminModules": {
@@ -1375,7 +1367,29 @@
     "embedHint": "Some pages cannot be embedded. If this one stays blank, open it in a new tab.",
     "notFound": "This module no longer exists.",
     "invalidUrl": "This module's address is not a valid https address and is therefore not shown.",
-    "loading": "Loading …"
+    "loading": "Loading …",
+    "form": {
+      "create": "Add custom module",
+      "edit": "Edit custom module",
+      "name": "Name",
+      "url": "Address",
+      "urlHint": "The address must start with https://.",
+      "category": "Category",
+      "nameRequired": "Please enter a name.",
+      "urlNotHttps": "Please enter an address that starts with https://.",
+      "urlCredentials": "The address must not contain a user name or a password.",
+      "saveError": "The module could not be saved. Please try again.",
+      "deleteError": "The module could not be deleted. Please try again.",
+      "deleteConfirm": {
+        "title": "Delete custom module",
+        "bodyShared": "Do you really want to delete “{name}”? The entry disappears from the sidebar for all users.",
+        "bodyPersonal": "Do you really want to delete “{name}”? The entry disappears from your sidebar."
+      }
+    },
+    "manage": {
+      "actions": "Actions",
+      "loadError": "The custom modules could not be loaded."
+    }
   },
   "moduleCategories": {
     "domain-tools": "Domains",