Standalone Office window / Office-only PWA for Nextcloud Office

Is your feature request related to a problem? Please describe.
Yes. When editing Office documents in Nextcloud Office, the editor is still opened inside the normal browser/Nextcloud UI context. For longer editing sessions, this wastes vertical screen space because of the browser address bar and surrounding UI. It also feels more like working in a browser tab than in a focused editor window.

The existing Nextcloud PWA support is not the same thing, because that applies to the whole Nextcloud interface. My request is specifically about Nextcloud Office only opening in its own dedicated app-like window.

Describe the solution you'd like
I would like an option to open Office documents (.docx, .xlsx, .pptx) in a dedicated standalone Nextcloud Office window, instead of always inside the normal Nextcloud browser view.

Possible implementations could be:

• an Office-only PWA
• a dedicated standalone window mode for Office routes
• an "Open in Office window" action
• a reduced editor view with minimal surrounding Nextcloud UI

The goal is not to make all of Nextcloud a separate app, but to let Nextcloud Office itself open in a more focused, app-like editing window.

Describe alternatives you've considered
I considered using the existing Nextcloud PWA / standalone mode, but that opens the whole Nextcloud interface as an app, not just the Office editor.

I also considered normal browser fullscreen, but that is only a workaround and does not solve the general UX problem. It still does not feel like a dedicated Office window and is less convenient than directly opening the document in a separate focused editor.

Another workaround is simply continuing to use the browser tab as it is now, but that is exactly the part that feels less practical for daily collaborative editing.

Additional context
This would especially improve usability on smaller or medium-sized displays, where vertical space matters a lot.

The main use case is:

• user opens an Office file in Nextcloud
• instead of loading it inside the normal browser/Nextcloud context, it opens in a dedicated editor window
• the editing experience becomes more focused and closer to a desktop office workflow

This request is specifically about Nextcloud Office, not about turning the whole Nextcloud instance into a PWA.

The issue names no files, tests, or entry points; begin with the Office document-opening flow and the existing whole-Nextcloud PWA behavior. Done means .docx, .xlsx, and .pptx files can open in a focused Office-only window without turning the whole Nextcloud interface into a PWA.