## Summary
- Changes the outer `MarkdownPreviewView` div from `.size_full()` to
`.w_full().flex_1().min_h_0()`.
- Before: preview's height stayed at 100% of the pane regardless of
toolbar size, so deploying the buffer search bar pushed the preview's
bottom 45px past the pane edge — clipped by the pane's
`overflow_hidden`.
- After: preview takes only the leftover main-axis space and shrinks as
the toolbar grows. Bottom edge stays at the pane bottom.
Verified empirically: `bounds.size.height` round-trips `952px ↔ 907px`
with the toolbar at `67 ↔ 112` (Δ = 45px = the search bar's height).
Companion to #55008 (anchor compensation). Both PRs come out of
investigating #54987 — they fix two independent bugs that surface
together when toggling the search bar.
## Test plan
- [x] Compiles with `cargo clippy -p markdown_preview -- --deny
warnings`.
- [x] Manual: `Cmd-F` in the markdown preview no longer clips bottom
content past the pane edge.
- [x] Manual: `Esc` restores the preview to full available height.
Release Notes:
- Fixed markdown preview content being clipped past the pane edge when
the buffer search bar is open
Co-authored-by: Agus Zubiaga <agus@zed.dev>
