Phase pages scroll naturally with mobile viewport fix

Photo grids no longer have their own scroll pane; the page owns scrolling. Mobile layouts now use dvh instead of svh for better viewport fit.

What's Fixed

Photo grids in the contents and inventory tabs previously had their own internal scroll container that capped the grid height at 60vh, creating a second scroll pane inside the page. This split the scrolling experience and made it harder to see the full phase context while browsing photos. Now the page owns vertical scrolling, and the photo grid scrolls naturally with the rest of the phase content.

Mobile layouts also switch from svh (small viewport height—affected by browser chrome) to dvh (dynamic viewport height), so mobile browser address bars no longer clip the work area.

Empty-state cards now have consistent flat styling across all tabs, and work-area padding is tightened for a more polished layout.