feat: wrap long text and add scroll in the TUI's content screens

[Etoile-Bleu]

Summary

• Long interaction descriptions and drug facts (e.g. Warfarin's boxed warning) previously ran off the right edge of the bordered box instead of wrapping. Enable Wrap { trim: false } on every Paragraph that renders variable-length text: results, drug info, and the shared message screen used for errors/no-match.
• Add Up/Down (one line) and PageUp/PageDown (PAGE_SCROLL_LINES = 10) scrolling for content taller than the terminal, on any of those content screens.
• Scroll resets to zero whenever the screen changes (App::set_screen), so a long result never leaves the next screen scrolled past its own content.

Test plan

• cargo build --release -p mensung-client
• cargo test -p mensung-client (43 passed, including 4 new scroll tests)
• cargo clippy -p mensung-client --release -- -D warnings (clean)
• cargo fmt --check
• Verified interactively in a narrow tmux pane: long boxed-warning text now wraps instead of running off the box, and Up/Down/PageUp/PageDown scroll through it correctly in both directions