refine post-install and hardware GPU docs, Monitor UX and CLI styling

- rewrite the 15 post-install pages and the 3 hardware GPU pages so they reflect the current scripts (reversibility, tracked-tool counts, kernel parameters, per-tool commands, Alpine LXC propagation flow)
- migrate the legacy step-badge helper on post-install/optional and create-vm/synology to the canonical pill component, with the stepLabel key added in each locale
- fix rich-text i18n calls missing helpers across network, automated, optional, security, customization and the post-install landing pages, and escape the `<iface>` placeholder in automated so intl no longer parses it as a tag
- remove the mouse-follow blue overlay from the docs landing layout
- reposition the App-tab Edit button and stack the Search and Register controls vertically on mobile
- move the Bulk update Configure/Edit control into the section header so it behaves the same on desktop and mobile
- show a spinner during the final autoremove/autoclean pass of update-pve-safe so the cleanup step reads as active instead of silent
- restyle the shell spinner and msg_info in a distinctive purple and drop the unused msg_lang duplicate
- add a web-docs i18n build script and its CI workflow, plus tests for the pushover notification channel

web/messages/en/docs/introduction.json

@@ -107,7 +107,7 @@
       },
       {
         "title": "Notifications",
-        "description": "Telegram, Discord, Email, Gotify and Apprise (multi-channel) — with deduplication, cooldown, burst aggregation, quiet hours and a complete history.",
+        "description": "Telegram, Discord, Email, Gotify, Pushover and Apprise (multi-channel) — with deduplication, cooldown, burst aggregation, quiet hours and a complete history.",
         "icon": "Bell",
         "href": "/docs/monitor/notifications"
       },