nightly-b5d7340

fix(layout): allow flex content to shrink so panels and rows do not clip

The middle column wrapping the header and view content had flex_1 but
no min_w_0, so it refused to shrink below intrinsic content width and
pushed side detail panels and right aligned actions past the window
edge on narrow windows. Adds min_w_0 down the chain through render
content, each view's scroll container, and the manifest row wrappers.
Side detail panels in Browse and Manifest now flex_shrink with a min
width so they compress instead of clipping.