feat(web): per-mutation success/error toast metadata (#47)

Declare meta on all 18 mutation hooks: meta.successMessage (toast.* key)
on every discrete user action, meta.suppressErrorToast where the consuming
component already renders the error inline. Corrected useUpdateFieldDefinition
to suppress (FieldForm renders update.isError as form.rejected inline).

Add an RTL+MSW integration test wiring the real MutationCache via
makeQueryClient() + ToastRegion: success toast, catch-all error toast, and
suppressed-no-toast. Tidy the toast Close aria-label to t("common.close")
with en/sv parity.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/i18n/en.json

@@ -1,6 +1,6 @@
 {
   "app": { "name": "Collection" },
-  "common": { "yes": "Yes", "no": "No" },
+  "common": { "yes": "Yes", "no": "No", "close": "Close" },
   "nav": { "objects": "Objects", "vocabularies": "Vocabularies", "authorities": "Authorities", "fields": "Fields", "search": "Search", "collapseSidebar": "Collapse sidebar", "expandSidebar": "Expand sidebar" },
   "auth": { "email": "Email", "password": "Password", "signIn": "Sign in", "signOut": "Sign out", "invalid": "Invalid email or password", "networkError": "Could not reach the server" },
   "objects": { "title": "Objects", "empty": "No objects yet", "loadError": "Could not load objects", "notFound": "Object not found", "prev": "Previous", "next": "Next", "of": "of", "new": "New object", "filter": "Filter objects…", "pageSize": "Per page", "columns": { "number": "Object №", "name": "Name", "visibility": "Visibility", "location": "Location", "count": "#", "updated": "Updated" }, "unknownRef": "(unknown)" },