The content type segmented picker rendered as a Liquid-Glass pill instead
of a native macOS segmented control. Wrapping a `.segmented` Picker in
`.opacity`/`.disabled`/`.accessibilityHidden`/`.fixedSize` (used to keep
toolbar items mounted-but-invisible for stable layout) inserts a hosting
layer that makes the toolbar fall back to the pill rendering.
- SearchView: filters button and content type picker are now always
visible on macOS, rendered bare so `.segmented` keeps native styling.
- SearchView: don't reset the content type to .video on submit on macOS,
so a pre-selected type (e.g. Playlists) is preserved (iOS unchanged).
- InstanceBrowseView: same pill fix, rendering the tab / content type
pickers bare via conditional `if` instead of opacity-masking.
- ViewOptionsSheet / MediaBrowserViewOptionsSheet: use `.formStyle(.grouped)`
for native macOS form styling in the options popover.
1157eef201