Port to ratatui 0.29

- Buffer::get{,_mut}() are deprecated, use Buffer[] instead.
  They panic under the same conditions.

- Define dummy cursor actions and a window size for TestBackend.

- Frame::size() is deprecated, use Frame::area() instead.

Cargo.toml

@@ -10,13 +10,13 @@ license = "MIT"
 edition = "2024"
 
 [dependencies]
-tui = {version="0.19", default-features = false, features = ['crossterm'] }
+ratatui = {version="0.29", default-features = false, features = ['crossterm'] }
 crossterm = "0.29"
 failure = "0.1"
 jwalk = "0.8"
 structopt = "0.3"
 filesize = "0.2.0"
-unicode-width = "0.2.2"
+unicode-width = "0.2"
 nix = { version = "0.30.0", features = ["user"] }
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["securitybaseapi","debugapi"] }