feat(export-import): add yaml export/import with id upsert for credentials, snippets, and scenarios

- all entities export a kind field (credential/snippet/scenario) for safe type checking on import
- import upserts by id: overwrites if id exists, creates with explicit id otherwise
- scenario export now includes id and step ids; import deletes old steps before recreating
- add GET /:id/export and POST /import endpoints to credential and snippet controllers
- add UuidBadge ui component: shortens uuid to first+last 4 hex chars, tooltip, clipboard copy with animated ClipboardCheck icon pop
- apply UuidBadge across all entity id display sites (detail pages, card footers, table columns)
- add export/import buttons to CredentialsPage, SnippetsPage, CredentialDetailPage, SnippetDetailPage

client/src/i18n/locales/en.json

@@ -71,7 +71,10 @@
     "field_last_used": "Last Used",
     "field_created": "Created",
     "field_updated": "Updated",
-    "section_data": "Data"
+    "section_data": "Data",
+    "action_export": "Export",
+    "action_import": "Import",
+    "import_error": "Failed to import credential"
   },
   "keys": {
     "col_name": "Key name",
@@ -116,6 +119,9 @@
     "action_add": "New scenario",
     "action_edit": "Edit",
     "action_runs": "Runs",
+    "action_export": "Export",
+    "action_import": "Import",
+    "import_error": "Failed to import scenario",
     "action_save": "Create",
     "action_update": "Save changes",
     "action_cancel": "Cancel",
@@ -228,6 +234,9 @@
     "field_description": "Description",
     "field_created": "Created",
     "field_updated": "Updated",
-    "section_code": "Code"
+    "section_code": "Code",
+    "action_export": "Export",
+    "action_import": "Import",
+    "import_error": "Failed to import snippet"
   }
 }