feat(nextcloud-status): Cloud-Formular zeigt nur deutsche Meldungen, Bildadresse auch per http (j9f)

- Vorabpruefung im Browser, API-Kennungen werden zu de/en-Texten
- Beschriftung Bildadresse mit neuem Hinweis zu http und https

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

apps/web/src/messages/en.json

@@ -1960,11 +1960,10 @@
       "logo": "Logo",
       "logoNone": "No logo",
       "logoUpload": "Upload image",
-      "logoUrl": "Image address (https)",
+      "logoUrl": "Image address",
       "logoUrlPlaceholder": "https://www.example.com/logo.png",
-      "logoUrlHint": "The address must start with https://. The image is loaded directly by your browser.",
+      "logoUrlHint": "Addresses starting with https:// are loaded directly by your browser. An image at an http:// address is fetched once by Tessera when you save and stored like an uploaded image. For images that can only be reached internally, please use “Upload image”.",
       "logoFileHint": "PNG, JPEG, GIF or WebP, at most 1 MB.",
-      "logoFileTooLarge": "The file is larger than 1 MB.",
       "logoCurrent": "Current logo",
       "logoRemove": "Remove logo",
       "save": "Save",
@@ -1973,10 +1972,23 @@
       "delete": "Remove cloud",
       "deleteConfirm": "Do you really want to remove the cloud “{name}”?",
       "deleteConfirmYes": "Remove permanently",
-      "required": "Please fill in customer name and address.",
       "saveError": "The cloud could not be saved.",
       "deleteError": "The cloud could not be removed.",
-      "close": "Close dialog"
+      "close": "Close dialog",
+      "errors": {
+        "customerNameRequired": "Please enter a customer name.",
+        "customerNameTooLong": "The customer name may be at most 120 characters long.",
+        "baseUrlRequired": "Please enter the address of the cloud.",
+        "baseUrlInvalid": "Please enter a valid address starting with http:// or https://.",
+        "logoUrlInvalid": "Please enter a valid image address starting with http:// or https://.",
+        "logoFileInvalid": "Please upload a PNG, JPEG, GIF or WebP image of at most 1 MB.",
+        "logoFileTooLarge": "The file is larger than 1 MB.",
+        "logoFetchInternal": "This image address can only be reached internally. Tessera only fetches images from the internet. Please use “Upload image” instead.",
+        "logoFetchUnreachable": "The image could not be retrieved from this address. Please check the address or use “Upload image”.",
+        "logoFetchNotImage": "There is no PNG, JPEG, GIF or WebP image at this address.",
+        "logoFetchTooLarge": "The image at this address is larger than 1 MB.",
+        "notFound": "This cloud no longer exists. Please reload the page."
+      }
     },
     "widget": {
       "loading": "Loading status …",