[EW] Metadata changes should trigger full page reload on QuickEdit

Reload the full page preview when metadata changes that can affect page-level rendering, rather than only updating the body. Metadata alters meta tags in the HTML `` like template, theme, or custom rendering flags, so a body-only update can leave the preview stale.

Consider:
- Debounce metadata changes to avoid a reload on every keystroke.
- Exclude standard non-rendering fields such as `title` and `description`.

Start at the QuickEdit metadata-change handling and trace how the preview currently updates the body. Identify which metadata fields affect page-level rendering, then ensure those changes trigger a debounced full-page reload while excluding standard non-rendering fields such as title and description. Done means the preview reflects relevant head metadata without reloading on every keystroke.

Written by the indexing model from the issue text.