fix(admin): keep cross-platform panels from overflowing

[CaYatur]

Summary

• Linux and macOS keep Genel Işık Ayarları, with Windows Dynamic Lighting-only controls and tags hidden. The WDL card stays Windows-only.
• Now Playing stays on Linux and macOS as manual title and artist. System reading stays Windows-only, and the untranslated SMTC sentence is gone from the English UI.
• Section cards measure their natural height before the 4px masonry grid, so choosing Çalan Parça no longer stacks every card on top of the others.
• Scene Generator and MilkDrop Preset Generator share the row when the window is wide. The English mash-up button wraps inside the card.
• A horizontal scrollbar no longer sits until the next redraw: cards cannot widen the grid, and the generator row is replaced in the same resize frame.

Test plan

• node --test on admin masonry, now playing platform, lighting general, milkdrop generator panel, layers, media session, and packaging
• Linux or a wide admin window: Studio generators sit side by side without a left-right scrollbar
• English UI: Use On-Screen Preset stays inside the card
• Windows: system Now Playing and Dynamic Lighting are unchanged