Shared Spinner component for button loading states

Adds a reusable shadcn-style Spinner (lucide loader-circle icon,
localized aria-label) and wires it into every button that has a
pending state: comment submit, delete, tag save, profile save,
admin saves, upload, login and register.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

package.json

@@ -16,6 +16,7 @@
     "@dnd-kit/abstract": "^0.1.21",
     "@iconify-json/ph": "^1.2.2",
     "@iconify-json/simple-icons": "^1.2.98",
+    "@lucide/vue": "^1.51.0",
     "@nuxt/image": "^2.1.0",
     "@nuxtjs/i18n": "^10.6.0",
     "@tanstack/vue-table": "^9.2.4",