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

AppImage/messages/en/common.json

@@ -1838,6 +1838,14 @@
         "toAddresses": "To addresses (comma-separated)",
         "subjectPrefix": "Subject prefix",
         "emailHint": "Leave SMTP host empty to use local sendmail. For Gmail, use an app password.",
+        "enablePushover": "Enable Pushover",
+        "pushoverUserKey": "User or group key",
+        "pushoverApiToken": "Application API token",
+        "pushoverDevice": "Device",
+        "pushoverSound": "Sound",
+        "pushoverCriticalPriority": "High priority for critical alerts",
+        "pushoverCriticalPriorityDescription": "CRITICAL notifications use Pushover high priority. Emergency priority is not used.",
+        "pushoverCredentialsHint": "Create an application in Pushover and copy its API token and your user or group key.",
         "enableApprise": "Enable Apprise",
         "urlFormats": "+URL formats",
         "appriseUrl": "Apprise URL",